Checkers sixty 60 keeping money not theirs

I placed my first order on the checkers 60 60 app on July 2 2021. According to their email a higher amount than my actual purchase would be reserved in my bank account incase other goods were substituted in my order. I waited until 18 July but there was no refund in my account. My order amount was less than what was debited from my account. Nobody rep**** to me. I checked with my bank who confirmed that there is no funds on hold. Now I must beg checkers for my refund. Why provide a service if you cannot manage it efficiently? Your Ticket ref 790559