Changed me to a by the gig plan without my knowledge or consent

My phone had been blowing up with texts from Xfinity mobile saying I’ve gone over my by the gig amount and will be charged overage fees. Not only did it show that Xfinity had changed one phone to by the gig but my bill was now showing 2 on by the gig plans neither of which I authorized or changed myself. After going around and around the rep says he got approval for a $20 credit instead of the $241 I’ve already paid plus the new overage charges.  I had asked that all charges be reversed and his best was $20.  It’s the old bait and switch which is VERY ILLEGAL and doing it against seniors is deplorable.  I have gone through customer support several times this week and each time they supposedly have it fixed we conveniently get disconnected!  I am ready to pull someone’s hair out!!!  Let someone do this to you or a loved one and you’d get straight already.  I’m completely over Xfinity/Comcast.  This is the last straw because they switched a line the same way a year ago!  The FCC will definitely be hearing from me as well as a class action attorney.  I’m going to get others who have been defrauded and stolen from by means of unethical practices. Their service went from great to horrible in under 6 years (I was a previous customer with my daughter without a problem).  I sit around 8 feet from the modem but only get 1-2 bars on the internet and the same on my mobile phone which is also on Xfinity. The mobile device I get mostly one bar when I used to get 4.5 bars before.  This is no way to treat customers that have been with you a long time.  It’s all smoke and mirrors and lies that you have to solve via lawsuits.  You are preying on the elderly, tech challenged and trusting people who believe you will take the set amount as stipulated in their agreement.
instead you are changing plans to by the gig to illicit funds that aren’t yours.  My God, have you no morals or conscience?  You steal our money then offer us less than a 5% credit.  It should all be credited back be cause you orchestrated the entire fiasco.  I hope I’m the last person you do this to because it is illegal.  My account was fine and my bills were $61 to $77 due to adding another line through another promo that also featured unlimited talk text and data…..so where did the by the gig come from, I ask you, Xfinity?  You, you and you is the honest answer.  All management needs to be fired but I’ll fight this in court and social media with others at my side.  In addition I will write to every applicable agency where I can file complaints against you.