"I sent out 1250 surveys and received 324 response" In this case, it was not a self selective group like an online poll, but a random sample of your customers, some of which responded. A phone poll works best as it makes it harder for them to select out. You method was second best, and the worst possible data comes out of any method in which the respondants select themselves. Such data is considered meaningless in the political research industry, and I suspect the same holds in marketing pollsters.

Truth has no value without backing by unfounded belief.
Renderosity Gallery