This morning I’ve visited my local 4 letter supermarket (like I do Mon-Fri) and got the same items (like I get Mon-Fri), payed Contactless with Monzo (like I do every time). However this time, I received an error about an incorrect currency - the screen showed that payment failed and I had to try again. So I did - again with Contactless option and the payment went through.
Only when I got to work I noticed that Monzo App (Android) is showing that I spent the same amount twice. It’s not a £100 transaction, but the error on the Self-Checkout machine was clear yet payment was processed. It did not give me a receipt on the payment that failed (yet got processed) and I did not take a receipt on the second payment as it was approved without an issue.
Any advice would be appreciated. I am not sure where the issue had originated.