Na de beëindiging van het contract ontvang ik nog steeds een rekening

When I left the Netherlands, I unfortunately forgot to cancel my telecom contract with Kpn. As a result, I’ve been charged for the past few months, and because of the unpaid balance, my phone number has been suspended. I only realized what happened last week when I checked my emails. They’ve terminated my contract, but today I still received another bill for this month. I tried calling them, but I don’t understand Dutch, and when I tried to get through to a customer service representative, I was on hold for a very long time without success.