Return with no refund or communication

I bought two tracking watches for my sons. It arrived and I put in on charge as per instructions. The watch turned on for a second then turned back off again. Both did the same thing. Could not function at all. I sent it back and it was confirmed that it reached the supplier on 29 January already. As to date I have not been refunded and no further communication received. Please beware of OneDayOnly. Their customer service is shocking. Next step - reporting to consumer protection.