Subscription cancellation after emigration not finalized?

Hello KPN team, 

As instructed by your team, I submitted my cancellation form due to emigration via the online form and included the stamped document from the gemeente (Amsterdam) which indicated that I left the Netherlands to live in the United States. I received the automated confirmation email confirming my cancellation request/successful completion of the form on June 1st but have not received any further confirmation that my cancellation request has been finalized. 

I also already returned the internet/wifi router in the same KPN packaging I received it in and included a page with all of my contact information, client number and the cancellation date. It was shipped via PostNL and shows that it was delivered to KPN on 7 June.

I am unable to call customer service as I am now abroad and the chat feature cannot support - it just keeps prompting me to schedule a call back but does not accept international phone numbers. 

May I kindly ask for some support in ensuring my subscription is cancelled per the date on the form/de-registration and that any funds paid since then are refunded, please? Thank you!