The IP address of our resolver in Istanbul has changed - the new IP can be found here.
I have also been able to add a new resolver in São Paulo, Brazil, thanks to HypeHost, who have generously donated a VM to the project.
Regarding the Stripe issue, I have given up on it. I don't know how other, similar projects do it, but they seem to be unwilling to re-enable our account without giving any specific reason.
Instead, I have added Bitcoin as another hassle-free option to donate to the project.