Mr Delivery has not paid back order canceled by the restaurant

I used the Mr Delivery app to order food. The restaurant couldn't take my order so the app put up a notice saying that I would get my money back straight into my account. I lodged a complaint about not having received my money and was asked to produce my bank statements twice. After that...silence.

I have received no feedback on the reasons behind this delay and they conveniently do not make a helpline easy to find. Absolute nonsense.