How do I get records of a line that was suspended 2 months ago?

Are you the Primary Account Holder (PAH)?  Is the line and account that line is on still active and is the line a postpaid line?  If the account is still active, you can login to your my.t-mobile.com account and see the list of calls and texts (numbers only) on the bill that covers the time frame you are looking for.  If the account is no longer active.  You might be able to have a store pull up the account and print off the bills for that time but only the PAH can have that done.