I have attempted their test and sample paper three times now, however, the result is the same. They tell me that I don't qualify their test.
I worked for them for 18 months before leaving the job
You qualified before but do not qualify now? A company whose test results are inconsistent and whose writer screening process is whimsical is hardly one which I would boldly declare legit. I am not claiming that they are scammers but only saying that the conclusion one draws from your posts is not in their favour.