Ridiculous service

So after having to complain on HelloPeter and numerous calls to Heita call center a retention advisor finally contacted me and assured me that the last debit order would go off my account on 31 Jan and that the contract which I have been trying to cancel from November 2015 would be cancelled. Low and behold, I received an invoice on 01/02/2016 telling me that the invoice dates are from *** and that the amount would be due on 29/02/2016!!!! On a cancelled contract. I tried to contact the call center, but after holding the line for 15-20 min without anyone assisting I just can not anymore! Please contact me to have this sorted!