[TrK]

I don't know why but for some reason they just deny mine and one of my friend's card for no reason. I tried contacting my bank and they say that it's all fine, but vultr does not accept it.

I think i gotta agree with @deanhills that they really do need to work on these basic customers problematic things.

Okay i don't think thats a problem in their end i mean vultr is working fine especially if it comes to processing money, there are certain reasons that your card is not working one of them could be International usage(including vbv), yes you read it right if your card is not authorized by your bank you can't use it to pay on websites who are using foreign payment gateways. Another thing it could be banned, as few banks card are not not accepted on some foreign payment gateways like qiwi its a russian bank allows everyone from the world to get a virtual account with a virtual visa card and these card won't work for most of payment gateways so yeah it could be your card is either banned or denied foreign usage. I suggest you to directly contact your bank's card division to look onto this matter.