Address no longer shows up in Bcoiner account
Unfortunately if this is a Bcoiner bug only them can recover your address and your Bitcoin.

When you generate an address, you generate a private key (linked to your bcoiner account) if Bcoiner can't recover it I'm afraid you have lost your bitcoin forever.

The best solution is then to contact them.

Remember : use a local wallet (Bitcoin-qt for example) and make a bakup of your wallet periodically, if you want to use an online service then make a local backup of your wallet to avoid this kind of problems.