Extremely Unhappy with FNB Credit Cards Department

FNB Credit Card is so unfair. They are so quick to send you payment requests every other day then once you pay your card fully , then they send you from pillar to post when you are requesting a letter as proof that you’ve paid the account fully. They don’t bother to respond to emails and the phone keeps on ringing non stop. You keep on getting emails that’s it’s been escalated but zero feedback