Being Double Billed for a Second Account an Xfinity Employee Created Without My Knowledge

I signed up for Xfinity service for the first time about a month ago online and decided to pickup at the closest Xfinity store to me for the self install equipment. I went to pick up the equipment for service a few days later and at the time I did think it was taking a bit of time to get the Xfinity router/modem, but the employee didn't say much to me and just typed on his computer for a while and that was it and after a bit I got everything and went on my way and thoght I was good to go.

I've paid for my first month of service on the only account I created when signing up (online), which included signing up for autopay and paperless billing and I thought that I was all set. Fast forward a month in and I receive a bill in the mail to the same address from Xfinity and thought it may be fake because the name was slightly different from mine, but it was close and it had a different account number on it. I went to the same Xfinity store the other day to see what was going on and an employee at this location decided to tell me the employee that did my pick up order a month ago input a second account so that he would get a sale and that this has happened more than once with the same person, maybe everyone working in that store for all I know. I was so lost for words because it was said to me to me like it was not a big deal.. that's fraud.

The original employee didn't attach the account to my email, but tied it to my phone number, same address, changed my name slightly, and this bill showed he signed me up for a different package with tv, phone, and a slower speed internet. I only signed up for 2 gigabit internet service when I signed up online for service. I thought I was getting spam texts about an Xfinity bill due, since my account was already paid for with autopay. I wouldn't have even looked into this, if not for the bill in the mail. 

This employee told me he got rid of this second account, but could not give me any proof of this with any print out for some reason and he told me to get in contact with Xfinity to get a credit for the wrongful billing. I walked out disgusted with the entire thing. So now I have this double billing issue, possibly a second account still open beacuse honestly I don't trust anything this store would tell me now. Is anyone at Xfinity able to help me this problem? I've never had this happen with any other internet provider before. Is this a normal thing stores do at Xfinity to get sales in?