Used to be good, till recently I found missing rebates frequently (over 70%). You can't file a claim within 30 days, and they expect you to forget after 3 months, so they can refuse to give the rebate back to you. I contacted the customer service, they said it's my fault, because my browser installed Ad-block, which is a shameless lie (I know what I am talking about because I am a software engineer myself). I use ebates too, never had any problem.
We're sorry that you had such a frustrating experience. We will always pass along cash back whenever we are credited for a purchase. If we have to deny you, it is because the store has either denied a claim or, with older purchases, will not consider an inquiry. In those cases, we are not compensated and thus cannot pass along cash back. We apologize for any inconvenience the 30-day waiting period creates, but reporting times can vary greatly (even with the same stores) so we give merchants a full 30 days to alert us to purchases.
Regarding Adblock, the program is known to cause some issues with many, but not all, stores' tracking systems. So some transactions may still be reported automatically while others are not. Since we do not control the tracking systems, we can only advise customers on the most common factors that can cause tracking problems. Since Adblock interferes with automatic tracking with so many stores, we ask customers to disable it -- at least during purchases. Customers who do this see their tracking issues eased.