Fed up with rcs all together

Im fed up with bad service and rcs all together. I regret the day i took their offer on this card.

I have a makro rcs card and been paying every month. So on the 27/7/19 i paid them more than what my installment was and it was never allocated to my account so i phoned and they said they will get back to me, 2 weeks went passed so i phoned again, after speak to 3 different people they said they will get back to me. Then i emailed them 6 times with the proof of payment and still no answer so i phoned my last airtime out because i received a bad credit email from rcs and then eventually they said the found the payment and will be allocated. Received my statement today ( after having to ask for it) and still nothing has been fixed.

Why is it so difficult to get rcs to fix what the did wrong?