Anyone else experienced a PAID line being added to their account without your authorization, and then had issues with T-Mobile when trying to remove the added line and get a refund?

Upgraded and bought a new iPhone in a T-Mobile store on 04/22/2022 - I am unfortanely just now noticing after reviewing my yearly reports for tax season approaching, that there was a data line added to my services/bill on the same day, for an apple watch?!  The charge was insignificant in cost enough for me to never notice too much of a difference, and the sales representative in the store explained to me the new bill amount and an increase being due to the monthly amount I would be charged for the iPhone payment plan option to pay month for a phone instead of paying in full.  
I am now trying to have the line removed but the customer service dept. has only tried to tell me I am wrong and that I activated this on my own MONTHS prior to 4/22/22, which is so far from true.  I have only ever used my apple watch on wifi/connected to my phone via bluetooth.  After reviewing my usuage overview for 2022, each month shows the additional line and every month has 0.00GB of data used.  I found this information through my t-mobile account but yet the customer service reps I’ve spoken to (which has been several now) all seem incompentent and unable to find similar information to show that this change was unauthorized. 
In addition, the representatives only focus seems to be on conversion or a new sale, rather than doing actual customer service.  What happens to customer service???  

Anyone had similar experiences?  What did you have to do to get T-Mobile to cooperate and help?  Do I need to file claim with the Better Business Bureau you think? 

Anyone filed with the BBB before, and if so, did you have any good results from it?  
I just want a line removed and something credited to my account for the near year I have paid for a service I never signed up for or authorized, and it seems impossible.