What the hell is buxtank?
Looks like an attempt to shill a shady wallet.
Out of curiosity, I check it out, and I have every reason to believe it's a scam wallet.
1. Asking for private keys
2. Once you send money to the wallet, you won't be able to withdraw or send it out
3. Asking to pay a monthly fee inform of an account level package, just like Ponzi schemes
4. Claim that you will be anonymous but will ask for personal information to sign up
5. Claim that only you will have full control of your funds, but there's no option to back up one's mnemonic codes or privatekeys