Payfast declines transactions without any reason

I tried paying with my Discovery Credit card, two different companies two different days. the only similarity is Payfast and Bank. Yesterday Spout Coffee company powered by Payfast using my Discovery Card, today Afritheatre again Payfast & Discovery. All transactions decline before reaching the bank providing a code Z8. I have spoken to the bank and they stated that there is no evidence of any attempt of payment using PayFast. Payfast does not even have a nr to phone to request help. This is a terrible insecure unreliable linkage. I am disappointed