I had the same problem with my new Mesh a year ago. First time it was a faulty motherboard, second time it was faulty memory. Eventually got a new machine but it was a long, bitter and unpleasent fight. I'm afraid you may have to keep nagging and arguing for some time to get satisfaction, but they seem to like it that way.
If you or they suspect it's a hardware fault they'll need the machine back so don't expect any on-site assistance.