It wasn't a gas test but I had a problem with a test and notified my scheduler. I knew I was giving the right answers but the test kept telling me there was 1 wrong. She emailed me back the next day and said there was a "format" issue and I had passed the test.
So in answer to your question: Notify your scheduler.
They make some of these tests like it's "rocket science" I was thinking of doing a couple fast food shops and the tests were "ZOWIE"!! I passed them finally then began to look at the after shop questionaire and it was 26 pages long....I kid you not...26pages long. Needless to say for $4 I am not doing these fast food shops!!
This is the same company I get emails from with a list of shops a mile long. And they wonder why they can't get their shops done...Boggles the mind!! LOL!!