where do i send my ONN tv to be repaired?

Does anybody know where do we send our ONN tv to be repaired. We have only had it about 18mths if that.
We took it to a shop that fixes tv's but he said he cannot fix it as he cannot get the parts to do it and these tv's are a bit of a problem.
It is coming on and then going straight of again and sometimes you would be watching it and then it would just go off.