HELP ME WITH THE POSTAL SERVICE!?

T-mobile sent me 2 phones because the other 2 on the account werent working. I sent them both back seperately but instead of sending ti by ups i put them in the us postal office shoot. even though the label on the boxes were pre paid for ups. which i didnt know:/ ... i DO have a picture of ONE of the box's labels but not the other. i tried calling ups and they said they didnt recieve anything but us postal service usually sends ups mail which was sent by accident to ups which will send to the original location it supposed to be sent to. BUT us ps said that they dont know if they sent it because they have too much mail and how are they going to know where it is. its been almost a month and tmobile will eventually fine us ALOT of money. what should i do??? anyone>?