Discovery Card and FNB giving me the run-around and I can't contact Discovery Card

I app**** for payment relief on my Discovery Card at the end of March 2020. Contacted Discovery Card and they said I must speak to FNB. Emailed FNB and no responses since end March. Now FNB is calling and harassing me for outstanding payments and say I must contact Discovery Card. Even though Discovery Card told me in March I must contact FNB! Now the two numbers given to me for Discovery Card KEEP ON going through to FNB agents and even if they put me through to Discovery Card, it re-routes back to an FNB agent. How can I make any arrangements if I can't even get a hold of Discovery Card through the numbers given. The run-around I have been given from March till now, as well as the total lack of service, is appalling.