Happy Pay - not a happy customer at all

The first purchase I made using them went very smoothly. The order and the repayments. Their payments deducted on time…all good. End of December I purchase from a merchant and use Happy Pay but this time atrocious! My payment was supposed to be deducted on 25/1 and 25/2 (two equal payments) but they put through both payments at once. I contacted them on the next weekday following their error ( they don’t work on weekends) and asked them to refund my one payment as they had put through my card amount twice. Oh, they said, we had a system glitch and I will have to wait 3 to 5 days for my refund. I had to force an apology out of them! I did not have enough funds in my account to meet both amounts and my account went into overdraft - a facility I prefer not to use. If Happy Pay had their eye on the ball they would have noticed the error and not waited for me to report it. They only actioned the refund on day 2 - so if it takes 3 to 5 working days to get my refund it could be well over a week before I get my money back. Needless to say I will not be using them again. I hope their CEO sees this but they are usually the last to know.