Trade in update

Had the same problem traded my 12 max pro 512 GB last July never received credit ….multiple calls with foreigners for months and never got resolved…..today I got an American on the line it did take over a hour but she worked hard and the end result was a one time lump sum credit for 800 dollars ….at 1 st I did think it was a scam but if you get the right AT&T representative on the line you’ll get positive results…..oh yeah you’ll need the IMEI number of the phone you traded in