Compensation for a delayed refund?

[Lexual]

I'm due a refund from a supplier, it was stated when I made the application online that I would receive it within 14days, it's now been a month and they are still saying it will take longer because it is an 'international' payment. It's 2018, it does not take 30+ days for an international payment to be received.

The amount is c.£900 which I could really do with right now..

Is there anything I can do to get some sort of compensation, or anything to cause them the grief they have caused me?

[Lexual]

Paid by card, eventually got the refund after over a month... but, they refunded twice by accident and are now requesting me to refund the extra refund as soon as possible!

The refund process may take a while. Karma.