Banggood UK review: Hantek ids1070a wifi (order id 105335705)

Hello,

Regarding the mentioned item above, I purchased it online on Banggood UK website on 26 November 2021. Paid for it in UK pounds, since I'm resident in the UK. Item arrived with one unusable part. After a complaint on same website, it was agreed that I should buy the missing part locally and be refunded on the value of that part. I did so, and sent them the receipt of that part. £7, 99 (UK POUNDS). Banggood only refunded me the value of $7, 99 (US DOLLARS). Which is obviously not the correct amount, due to the exchange rates. Complaint again on their help centre, they absolutely refused, in a very arrogant way, to recognise the issue and make matters correct.
Several emails sent on this issue remain unanswered.
What can be done about this?
Thank you

Nuno Tavares