Unused connection in my old apartment being billed since October 2023. Impossible to reach KPN and cancel this

Wrong charging contract. and I cannot success to find the right path to contact. link of complaint is terrible and always bring to chat bot. I really need to contact staffs.

Last few day, I success to make a call with your call center and I tell all story and she recommend me to send the complaint. but now I cannot find it. 

My problem is since OCT 2023, i did start with KPN at my old apartment. then in meantime, once I recieve modem, the apartment owner said they can offer Ziggo. then I call and requested to cancel KPN. and even contact to return the modem which I haven't use, connect or activate. which you can check from system. but there is no responding from KPN at all. then I forgot about it. after all, I just found that the contract was not cancel and keep charging to my debit card automatically 5x.xx EUR/month for over 2 years. which approximate cost more than 12xx EUR. so I want KPN to respond how to return my money. 

Now i am using KPN for my new apartment too. so in case it can used as credit and deduct. Please kindly help respond. it is so so much difficult to contact you guys. and believe me your CHAT BOT is not performing correctly.!!!!!