Poor customer service

I went for a cause on the ,04/03/2023 for CPR venue was virgin active Wonderpark and Instructor was Bheko and till to this day I have not received my certificate I was told by a lady at virgin active that I didn't pay.As St John were the one offering training which I paid with proof payment I demand the certificate as is over 31 days now. I believe St John is after money as this matter has been dragging for weeks now asking for my certificate if it can't be done I am kindly asking for a refund.