I can't request a compensation for a malfunction that lasted for 9 days

Hi @compensation, welcome to our forum!

The standard procedure for compensation is through this page: kpn.com/vergoeding
If that doesn't work the quickest way is by giving us a call on 0800-0402 or chatting with us on www.kpn.com/service

Otherwise I can also take a look here but the response might be a bit slower. Could you update your profile and let me know?