How to return money that I over paid for 2 line I did not Use

How long wer you charged?

For 4 month 

Since February 

If I understand, you are probably looking for a refund because you have been paying for service since February that you aren't using.

If this is prepaid, there is no refund. Prepaid service ends when you stop paying for it. It can be as simple as turning off the auto pay switch in your online prepaid account. Or porting your number to a different service provider.

If this is post paid it was up to you to cancel service in February when you were done using it. Either by porting your phone number to a different service provider, or calling AT&T to cancel any phone numbers that you were not porting.