Thank you all for your comments. I found the problem. All tests, from multiple WAN connections, went through a Fortigate firewall. This performed package inspection, I think he has shown that the ports are open because of the inspection. We tested it...

#show run | i serviceservice tcp-keepalives-inservice tcp-keepalives-outservice timestamps debug datetime msec localtime show-timezoneservice timestamps log datetime msec localtime show-timezoneservice password-encryptionservice sequence-numbers

Yes i have, on the Dialer.interface Dialer1ip access-group Public_ACL inip access-list extended Public_ACL1 deny tcp any any eq 8010 log 2 deny tcp any any eq 8015 log 3 deny tcp any any eq 8020 log

See the screencap  

Thank you for your information, i have but the port still says open.. i have it with multiple Cisco C1111-4P. Like 200 of them..i have forwarded the port to a unknown (not configured) ip-adress as a test, but it still says the port is up.