their bank is not there i am sure it estonia or somewhere like that.
I have an account at Bitstamp, and when I want to deposit, it displays GORENJSKA BANKA, which is a Slovenian bank. It might be that they use more banks within the Euro zone, but this at least shows that it isn't Bulgarian.
And another thing, Bitstamp isn't located at Bulgaria. It was a Slovenian exchange at first, but due to legal reasons, they are currently based in Luxembourg, where they were also granted their license.
That license allows Bitstamp to function as money transmitter, which is something a lot of the current exchanges can't say. They almost all are illegal money transmitters, which at some point may cost them badly.