Still being charged despite canceling based on emigration

My husband and I both canceled our subscriptions in November providing documentation that we emigrated from the Netherlands and the form was acknowledged as received. But we are still being charged for our phone lines. I even canceled my subscription a second time, providing documentation, and was acknowledged, although then they stated they would cancel it on Feb 17th...more than a month after I requested cancelation (for the second time!)?? They can see we haven’t used our lines for several months now, it’s not like we are trying to get free service...we are just trying to cancel a service we no longer need. Why is this so difficult? And why is it so difficult to contact KPN outside of a myKPN (which we can’t use anymore because we do not have the number to verify) or calling them (and they won’t call a foreign number)??