Discovery won't return my R3000

I had a Discovery Credit card through FNB which i closed many years ago. The account appears on my FNB Internet bank app. I accidentally transferred to batches of money from my savings account to the closed Discovery Credit Card. I immediately contacted Discovery and was assisted by Beatrice. The one batch of money (the smaller amount) was refunded to me. The larger amount i have been following up with Discovery for over three months now. Beatrice no longer responds to messages for her to return my calls, I submitted all documents required on 7 January 2022 already and was told that it takes about 1 week. I have been begging Discovery t return my money with no responses. This is unfair and i need assistance.