I'm being overcharged due to several mistakes Xfinity representatives made

I will describe my situation in chronological order followed by my requirements.

Early 2025, I have a line, ending with 0222, let's call it line A, with Xfinity in a family plan account, ending with 2357, let's call it account X.
In August, I enrolled in a Xfinity internet plan account, ending with 8861, let's call it account Y. That new account comes with a promotion of a free Xfinity mobile line.
On September 1st, I made a phone call to transfer my Xfinity line a from account X to account Y. However, that representative made a mistake and deactivated my line A ending with 0222, and activated a new line ending with 7931 linked with account Y. Let's call this new line ending with 7931 line B. 
At this moment I have line A deactivated, and line B activated, linked to account Y.
On September 2nd and 3rd, I made several phone calls to activate my line A again and link it to account Y because I wanted that number so badly. After several complicated process, I finally reactivated line A again.
At this moment I have line A and line B activated, and linked to account Y.
Starting from October, I have received the extra bill for line A or line B for about 29.99 per month, since one of which (I don't know if it's A or B) is free.

Here's the background context, and my requirements are: 

I would like to have my line A ending with 0222 still active and linked with account Y.
I would like to deactivate line B ending with 7931. 
I would like to use the promotion of account Y for line A, so that I do not have to pay for this line for one year.
I would like to request a refund for line B, which was created by a Xfinity representative misunderstanding my requirements, and never used later. 

Feel free to contact me through my phone (line A only) or email for extra information.

Regards,