From outside, debt collection in Turkey may appear as complicated. However, the procedure to recover an unpaid debt, due to invoice or contractual clause, is quite similar to the systems in Europe. 

The first stage is the notification of the debtor, which is generally needed to render the invoice amount "mature". In other cases, there is no need to prior notification procedure.
As from the delivery of the notification, the debtor side may contest. To do so, debtor shall act within 7 (seven) busines days. Otherwise, the notified amount or invoice will be considered as accepted by the debtor. 

In such a case, the creditor may immediately proceed to the enforcement of the debt, by initiating a procedure at the competent Enforcement Office. This judicial body is empowered to proceed to the investigation of debtor's asset and realise the payment of the debt, even by seizures on movable and immovable property of the debtors.

But in practice and majority of cases, the debtor side do contest the notification.
Then the creditor shall initiate, not later than one year, a law suit on the merits. Such a legal proceeding is aiming to request from the court to dismiss the contestation of the debtor. 

Law suit on contestation of debt collection in Turkey takes around 1,5 years before commercial courts. The convenience for the creditor side is that if the court judges that the claim is rightfull, then the debtor shall pay an additionnal 40% (forty percent) indemnities for abusice contestation of a righfull claim.

Once the final judgment is notified, there is no way for the debtor to hide, especially considering the fact that it had to declare its assets. This may end the debt collection in Turkey, even before the final judgment, by transaction.