Hi Tony,
Unfortunately, it's not uncommon for suppliers to treat email inquiries as non-priorities, even ignoring them completely on many occasions. It's a real blight on their level of customer service, but it is far more common than you would suspect.
Many treat email inquiries is a nuisance and a waste of their time, it's one of my pet hates and I'm quite sure that I'm not the only one. If possible, the best way to contact any supplier is by phone, that seems to be the one line of communication that no one ignores or should I say, not many ignore!
Cheers