Make Believe Co. review for Google & YouTube

I have given up on this App now. The GTIN error which appears on all my products now just doesn't get fixed. I have read articles, tried everything and reach out to support and was given a 'solution' which doesn't make any sense and doesn't apply to 'non-custom' products. Great, that its free! But not great that it actually doesn't work properly. I have seen so many stores asking the same questions but there is no solution.