database functions for membership plugin

Membership plugin. I've run a few payments through paypal, and they go through alright. The problem im having is the user isn't then added to the subscription plan they purchased. Ive checked the databases and they arent added there either. Transactions aren't being added to the database either. has this issue come up before? what was the fix? I've tried deleting the plugin and dropping the database tables. then reinstalling it. Still no luck. If your not to sure, can you point me to where that function is in the back end and i might be able to find the problem and fix it. Cheers