I have been trying to withdraw a balance of around 1.2M GBP from Bitstamp for the last month. 

It has repeatedly failed.  They keep sending me in circles and fobbing me off.  I have raised several support tickets, and on Friday I raised a complaint via their complaints email address.  In my last support enquiry, I told them that I would have to treat the funds as stolen, if they tried to fob me off again.  But, they tried to fob me off, with some supporttard telling me to clear cookies and cache (classic fobbing-off technique), and closing the ticket.  So I do now have to treat the funds as stolen.

Although their domicile has always been unclear to me (elements apparently in UK, EU, US, and customer relationship apparently being moved between "entities"), it has always seemed to have a UK presence.  Therefore, I intend to raise a complaint with the FCA, and with the Serious Fraud Office in London.

My suspicion is that this is similar to when other exchanges in the past have started failing to execute withdrawals: that their client money account(s) do not match their client balances, or put more simply, that they have stolen client money.

The exact pattern has been: I enter my GBP bank account details as per the form, with IBAN etc.  I submit the withdrawal request.  I get an email saying it failed, and for GBP I must enter account number in IBAN / account number field, and sort code in SWIFT/BIC field.  I then try to do this, but their form won't accept it.  When I enter the six digits without dashes, form validation fails in one way.  When I enter it with dashes, it fails in a similar but slightly different way.  I then raise the issue with them, they fob me off / incorrectly tell me it's fixed, and I go through the cycle again.

I am going to assemble an exact timeline, screenshots, ticket text, etc, ready for submitting the complaints, and will update this thread with more details in due course.