ATT agent kept out trade in phones

I call ATT about my internet service they send a wireless sale agent out who convinced my husband to switch out family plan from T-mobile by telling him our phones we paid in full from will be credited and all we had to pay was $5.56 per line plus $166 for the phone plans after calling every month about the bill credit we were promised, ATT told us that none of our phones was good and only game is $35 for 1 phone and my daughters IPhone 14 with 512 gig disappear and there’s nothing they can do about. Now we are stuck paying a high (Edited per community guidelines) phone bill every month that changes every single month bill and charges us to use it on the wifi out side of the country even if the phones are off