New Mobile Device Faulty

We received a device last week on the 1st of February, it is faulty! I've been trying to contact you via all your channels, no one has bothered to get back to me. I'm inconvenienced sitting with a device that automatically restarts while on a call. This has been happening since day 1. 1. You are not answering your lines. 2. You ignore twitter 3. You have not responded to a contact request sent via your website. The only thing you know is sell, once the device is with the customer. You disappear.. Please resolve this ASAP. You are inconveniencing me. I seemed advice from Huawei, they responded within an hour advising me to return the device as I'm still within my 7days. It's day 7 today, what now! Appalling service!