I realize this is a Paypal issue (probably, maybe you have the security settings too tight), but you may want to warn people on the subscription page.
I'm trying to sign up for Toolship, and it PISSING ME OFF! The problem is a catch 22:
1. The card I'm using is not showing up in my available Paypal cards when I try to pay using my Paypal account. The only one that's showing is now dead (I cleared and cancelled it).
2. Despite the above, if I try to circumvent my Paypal account and use the card directly, it won't let me because the card exists on my Paypal account.
In other words, Paypal won't let me use use the card on my account, but it won't let me use it outside of my account because it is on my account.
After a lot of wrangling I think the problem is that my card is not "verified", which can be done through Paypal but takes a few days. I'm okay with that, but I've spent 30 minutes fighting with the damned thing. I'm still going to subscribe, but the headache is not much of a motivator to do so!