More and more hosts are disabling that function actually. So if the people you bought this from truly are “the best” then I’m sure they realize that and if you e-mailed them they’d be able to give you a workaround or a new version that doesn’t use that function.
As has also been pointed out above (although you must not have seen it) there’s nothing stopping you from running your own version of PHP with that function available. Check out the wiki for instructions.
I had two different scripts that used that function one was part of ExpressionEngine. The Devs there had a new version out in less than a day to fix the issue. I’d hope “the best” people you bought yours from would be able to do the same.
bryan | website