They will just take your money and not activate your account.
You can't contact them securely, because their only support contact is email but the PGP key on their website is corrupted (you can't re-wrap the lines of a PGP key!) and even after fixing the corruption it turns out that they forgot to publish their encryption key (the published key is signing-only).
So there's no secure way to contact them.
Total waste of my time and money. This is why everybody uses Mullvad.
I have used them back when they cost 3.5€/mo instead of the 5€/mo you pay for mullvad or ivpn. Gave them a try specifically because the support XMR, and it worked flawlessly for each of the 5 (?) payments I made. Service is fine, no complaints, but the desktop app is shit. Can't easily configure local bypass which is supported by mullvad/ivpn. At the new pricing their offer doesn't really make sense anymore.
I also don't understand why websites are still using bespoke hand-rolled XMR payment frontends -- unless they are exchanges or (like localmonero) super-Monero-gurus... BTCPay server's Monero support is so good at this point... I have used it uncountably-many times and not once had any kind of problem.
Please folks, if you're going to accept Monero, consider using BTCPay Server.
One secure way to contact them is through matrix. First, make sure the transaction was completed for the correct amount net of monero transaction fees.
I had a positive experience using xmr. But I contacted them about their crappy pgp key months ago, they did nothing. I contacted them about many websites not being accessible from some of their servers, they did nothing.