When I was in Ziraat bank the cashier did say that although they can see the amount owing for SGK on their system, they can not see a breakdown of what that amount consists of (I went in expecting to pay 2 months but it was showing a higher amount due which did equate to 3 months payment, however the cashier couldn't see these details on his system). So there is obviously some link between SGK & the bank's system but not a full one. Just keep hold of all payment receipts.