Pay back the money

My partner tried to order food from the App on the 02/05/2020. The App had so much technical issues, assuming due to everyone trying to order food. The money was debited from his account however we did not receive any food nor did we get any refund. We have sent numerous emails to their email address and loaded complaints/enquiries on their website but have not received any response. We would like this to be attended to and resolved ASAP.