Incorrect exchange rate applied

I made a purchase of €40 but Curve seems to have applied wrong exchange rate (£1 = €0.80 instead of £1 = €1.16) and charged my card £50. Has anyone else had this happened. I have already contacted support but just wondered if other had this issue, as it’s first time this has happened to me.

this is just a pre-authorization, amount is always 50 GBP at petrol stations. you’ll be charged with the correct amount