TO: ImHash
Okay, So what do you think have happend? is it probable that the bcoiner wallet is a scam and that they have stolen my bitcoins? Is this a common problem? If this is the case, what do you recommend me to do? Police report? what?
Well... Bitcoin is basically a decentral database containing every transaction ever made. In order to generate a transaction, you need the private keys from the address containing a bitcoin balance (inputs).
What you basically did is: you gave an online, probably anonymous, company your private keys to manage your adresses.
It would have been a better idear to manage your own addresses by running a local wallet (bitcoin core, electrum, multibit HD,...).
Because the online company manages your private keys, they're the only ones that can solve this problem. This forum has dozens of complaints against various online wallets... Sometimes they turn scam, sometimes they go bancrupt, sometimes they have a bug,... There's not a hell of a lot we can do to solve this i'm afraid.
About what you should do: it's basically up to you... If it was a lot of money, and you can find real contact or company details, you might go to the police. If it wasn't a lot of money, or there's little identifying information, there might be little you can do.
My thoughts: isn't it really strange and bad that once a transaction is made, there is no way to get it back? Imagine if this were the case for every transaction between bank accounts for "normal" money? Imagine every time someone sends the money to the wrong account? Imagine if there was no way to recorrect the error? This is really not good for the future of bitcoins in my opinion.
This is how bitcoin is made: there's no central authority, no bank, no governement,... Just a public database that can be downloaded by anyone. So there is nobody to refund or rollback any transaction. This is one of the reasons most bitcoin users like bitcoins, but i do understand it must be frustrating to lose a lot of money.