Bad business

Bought 5 items 13 June. Received it 22 June. One item out of stock, 2 items not working. Reported it and received wayslip for courier. Send with courier 23 June. Since then struggling to get refund or any responds. Once managed to get David on line 29 June. He promised it will be sorted with refund. Since then no responds via e-mail, telephone messages, etc. Is there any where one can lodge a complaint against this company