Adding new line causes issues?

Recently I added new line on my family and friends plan.  System automatically created free line which added my bill amount more. 

I am checking with Customer service agent and they will remove the unused line which got automatically added only through next billing cycle.  Customer service agents are saying not able to change the current billing amount and they are not agreed to adjusted in future bill. 

This added additional $60 dollars on current month billing cycle.  Automatically added service charge, protection plan, Tax charges for the line which is unused (automatically added line).

I called T-Mobile store where I got the new line and they are saying system automatically added the new line (promotional offer). Store manager asked me to call customer service and get this unused link cancelled and the amount will be returned.  But no luck with T-Mobile customer services.   I am reaching out to customer service 3 times ( each call went more than 2 hours).

Is anyone facing this issue?  I want to have the permanent solution on this issue.