Poor service

I had an account at stern jewelry which i paid up in 2019july 13. Iwas so puzzled last year when i wanted to buy a new home that i am owing stern i went to stern brach i was told that my account has been ganded over i called their customers service their couldn't give details of their collectors thier asked for aprof of payment but i lost it i still have prof of EFT i have send them that sms but thier still cant. Lear my name nor give me their debt collectors details what kind of services is this are their really that ***********. Am falling to buy my kids a home cause of the money I paid am willing to pay ot but their cant let me cause their cant give their collecters details