MyPoints.com won't let my credit card through!

[house_of_princesses]

I went to the MyPoints.com site, linked through to DS, filled my cart and when I got to the payment page, I got an error message stating they could not access my credit card company. (Disney Visa!) So, I called DS...they couldn't help me, so I contacted MyPoints.com (via e-mail...can't find a phone number anywhere) and they say contact the vendor.

I have this probelm every time I use Mypoints, but don't remember how to fix it because I don't use Mypoints often. Something to do with security....I remember typing in mypoints.com somewhere, but can't find that somewhere.

Can anyone either tell me how to allow mypoints.com through my computer or how to contact mypoints.com via phone?

Thanks so much!!