Cubot: no response to help request for faulty Cubot V2 tracker watch.

My son's Cubot HR tracker watch has stopped working. It appears to be a loose connection as it works when charging but not when on his wrist.

I contacted Cubot last month via the Contact Us form on their website (the tracker watch was purchased in September 2017) to find out warranty details and to see what they advised - could it be repaired or was it better to replace it. No response.

I forgot about it for a while and have contacted them twice this week (again via the website) to ask for help. Both those contacts and requests for help have been completely ignored. Not an acknowledgement, reply nothing. Customer service that sucks. I wonder of it is deliberate and they are waiting for the tracker to be out of guarantee?