Why am I being charged?

I cancelled my Att uverse account. The same day I gathered up all the equipment and took it to ups to ship.  The same day!!! I then get these messages from Att that I didn’t turn equipment in. This is absolutely incorrect.    What am I suppose to do? Now it’s on collections and I 100% turned in the equipment the same day! Someone needs to please email me at JeremyRussotti@gmail.com

im hearing to contact FCC tomorrow and start a case.  Anyone else have ideas ?