My Paint Tool SAI license isn't working?

I bought the license, and received an email confirming it. Yet somehow, every time I try to open it using SAI it still tells me that I need to buy a license to continue using it.

I have a lenovo laptop with windows 8. Could anyone help?

Added (1). Well I uninstalled it and found out that maybe it's the program I opened it with. Do I open it with SAI? Because immediately after I entered that last time it gave me the message about the trial period.

Contact them and try to resolve it. Have them open up a ticket as evidence that they attempted to help you if this does not work contact your bank to cancel the purchase.