As mentioned, the donation number is your username and password for configuring add-ons and apps. You didn't donate directly to any of the services here, since Paypal is not used at this end. You made the donation through a reseller, which is not the best of ideas. You need to contact the reseller directly for your donation number if you do not have it.
Once in a great while a Super Mod can track down your data, but that doesn't prove successful very often.
