Haha, no, it's not my site. I simply plugged their receiving addresses in to block explorers for the relevant coins you mentioned (BTC, ETH, and LTC), looking for an incoming transaction made around the same time as your last post for roughly the correct value. Everything on most blockchains is completely public. Knowing an address is all that is needed to look at all transactions involving that address.

I wasn't aware Mozilla were offering a VPN, but on closer inspection it runs on the Mullvad VPN network, which is one of those recommended by privacytools.io. Do they accept bitcoin payments?