Refund less than purchase price

Description

Hi, I bought furniture from a uk store end of nov 2020 and paid 180 GBP and 210 euros was deducted in my bank account. There was a problem with it and I was issued a refund start of December for 180 GBP which equated to 199 euros. I was told the difference was the currency conversion in the two different days but that wouldn’t account for the big discrepancy. Are there hidden fees on the purchase or what is the reason? Thanks S