Discovery Credit Card

I am currently overseas and have been paying my discovery credit card religiously since i opened the account many years ago. I paid my card as a beneficiary on my FNB app, then two months ago all the details for my discovery credit card on my FNB app disappeared. I tried to get in touch with Discovery credit card division, but no one was able to help. I then managed to add my discovery credit card as a public service on my FNB app and by miracle it went through or i hope it went through as payments were accepted? Today i want to make my monthly payment and all of a sudden the app will not allow me to make any payments to my discovery card, so what am i suppose to do to pay my card, I have sent mails, i have done everything i can but nothing. So what now? I am so fed up, trying to do the right thing and pay my credit card, DO YOU NOT WANT MY MONTHLY PAYMENTS DISCOVERY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!but these bad service issues prevent you from doing so.