worst experience in my life with any kind of service

This has been my worst experience in my life with any kind of service or product. I simply wanted to upgrade 1 of my phone lines from an iPhone 13 to a iPhone 16. I started with the chat, which is ridiculously difficult to get past the automated answers section then calling and talking to agent, which even to get to them is next to impossible. Several of the times after a long conversation only to realize that they were internet people not cell phone people, to be transferred and start over my my issue. Anyway my problems had only just begun. Nice lady on the phone said no problem to get my phone upgraded with the current promotion of saving upto $830. She Promised to get it done and I should check back in 24 hours on the status. After two days, again after a lengthy process of getting through to anyone that could help, I was told something was wrong and I'd have to go into a store to get it fixed. I took  off time from work and headed to the Xfinity store at Willow brook mall in Houston, TX. I Waited patiently to speak with a store person. Only to be told something was messed up and that I would have to go sit in a corner and connect with a agent through a remote agent. After back and forth with her and several times having to go back and get the store person. I was told that neither of them could help me. Again remember all I wanted to do was upgrade one of my 5 phone lines from an iPhone 13 to a 16, and see what I might owe after the "save upto $830" promotion was. At this point I was told to call a phone number and they could help me. I lost it at this point and demanded to speak with the store manager. Was told the manager was not available and I should just go call this helpline phone number, which was where I gad started with in the beginning and had already been talking with them for hours and they told me to go into the store. I simply asked that someone take care of getting me my phone upgraded. I raised my voice and demanded to speak with them manager, was told again one was not available At this point the security guard came at me in a very threatening manner with gun and taser bullet proof vest and told me to leave the store. I was told at that point if I leave now the manager would call me as soon as available. I never received a call and have still not heard from that store manager. At this point I drove to another store and was greeted by a very nice very polite and professional lady, named Alicia. She finally was able to understand what was going on. She still couldn’t help me but did explain that the help phone people had "messed up" my account. They had switch my 5 phones from Xfinity post paid cell service to prepaid NOW service and now I was not eligible for any up grade and would have to pay full price if I wanted a phone or I would have to contact the NOW people and get them to switch my phone back. So I started that process. After several hours of going through your help systems, got someone to commit to changing my phones back and that it would take 30 minutes. I was still at the store so I figured I sit and wait. 2 hours later and 15 minutes before the store closed I had not gotten an email confirmation about the phones being switched back, so I went back in the store and they confirmed they had not been changed back. They Suggested that I give it some more time then call/chat to check on progress. That is where I was today. I began the process again of trying to get an update. After several frustrating tries to get a real person in a chat, began a 3 hour long run around with a chat string that I will attach. Still with no clear resolution, but again I was promised it will be fixed. I'll believe it when I see it. During all of these interaction I was always told how sorry and sympathetic everyone was and I should be assure that they would get my issues resolved. Even right now I still don't know how to get my 1 line upgraded from a 13 to a 16. This is my daughter's phone line and I wanted to do something special for her. I will do anything and  go to any length for my daughter, so I will not give up on what has now become a quest to stop a large stupid ignorant corporation Xfinity from thinking if they make it difficult enough I'll just go away. I will not. At this point I am estimating I have communicated with   20+ people that all said they were going to help me only to either transfer me to some else or ask me to leave your store. Nobody had taken any responsibility to fix an issue that Xfinity caused in the first place. I have never been so disappointed and disgusted in how I have been treated. I have also asked to be compensated for my time and effort, but any amount could not come close to the time, stress, frustration by me, and the disappointment my daughter now has in her father for not being able to complete a simple task of getting an upgraded phone. I would like you to try and make it up to me but first resolve my issue....I'd like to please upgrade my iPhone 13 to a iPhone 16. How sad all of this for a simple request… How much can I pay you so I can get a better phone that you have spent millions of dollar advertising.