Internet bill complaint

I canceled my mobile and Wi-Fi on 13/24/24. I cancelled because I went in Xfinity office in NLR AR and in Nov/24 added my mobile to my Wi-Fi. The representative said my Wi-Fi premium would go down and my mobile. They said there was a promo of $200 to be applied to my account. Then somehow the credits were not applied and my bills were all wrong. I spent much time online with Xfinity trying to get things straightened out to no avail. I went into the office in NLR and they said they could not help me. I tried many times to chat with Xfinity and each time no one even knew what I had said in prior conversations. Due to no communication I decided to go into Xfinity office to cancel my mobile and Wi-Fi. That was on 12/24/24.  That day I called Xfinity to cancel Wi-Fi. I had previously found out my Wi-Fi payment was going way up in price and customer service said they would lower premium a little and hold for a bit for me to make decision to cancel or not. My contract was about to expire. So I did go into the store and canceled my service. Then I was told my last bill on my mobile would be $25.95, not $65.90 as billed. Then they said since my promo credits had not been applied and, that the Wi-Fi would not be charging anymore bills. Since then I continued getting text saying I needed to return router which I already had taken in on 12/29/24. Then I have recieved text that said O will be turned over to a collection agency since they said I did not return equipment. Then on 1/9/25 I got another bill saying I owed $99.99. I called customer service and lady said I did not owe another bill on Wi-Fi and she would go in and credit $60 on the $99.99 and the next day credit $39 and that way I would not owe anything. Her phone was 18883662278. She sent follow-up text saying she had taken care of problems since billing we’re all wrong since November. I also received in the mail a memo stating no billing but that I would be receiving a refund of $58.40. I on 1/29/25 called customer service, that they mistakenly drafted $35.94 mistakenly on my mobile. She said they will open up a ticket to investigate. It would be one week til they would know something. Then I get memo that I owed $59.85 and I called again. She said she would fill out a ticket to investigate and they would be refunding the $35.94 in 7 to 10 days. Today I called customer service that I have not received refund on Wi-Fi of $58.40 and they say they are now charging me $110 for a penalty for cancelling my account and that I will get no reimbursement of $35.94 on mobile and no refund on Wi-Fi of $58.40 and that I owe another $59.00. I have spent hours each week to straighten this out. Every time I chat, no one at Xfinity knows what is going on. Remember I have a memo from Xfinity saying I will receive a refund on Wi-Fi of $58.50. I need corporate help and someone to call me directly. I plan up follow up in a few days by filing complaint with the Better Business Bureau and with the FCC. Please reply ASAP. [Edit: Removed Personal information]