Debt By Association- not a legal thing

My parents both passed away and my brother and I inherited the house. Now I opened a new account when we moved in and they rolled over my parent's debt into my account. I called and discussed this with someone and was told that I owe to the debt because of debt by association. This is not legal, and I don't know what to do to get this resolved. Everyone I talk to gives me a different answer. 

Plus, once I opened the account, after a mess where one account was opened, then closed, then a new account was opened...I have not received a bill or been able to access my account online. I also thought I had set the account up on autopay in the store, however after a couple months I realized the bill was not being paid. I had to go back into a store and get the account fixed so I could access. I am not being told I can't set up a payment plan because of the amount of debt- when 1/2 of it at least belongs to my dad. I don't know what to do because, unfortunately, only Xfinity operates fast enough internet for my business  in my area. Once Google Fiber gets connected I will probably switch. I am currently debating about trying AT&T and just saying goodbye to Xfinity.   Does anyone have any advice?