[morphios]

I already tried resetting, they just loaded their config back remotely.

---

I'd like to forward some ports.

How do you mean "they load their config remotely"?
Unplug the internet cable after the reset, log in and so your thing making sure to change any admin passwords and deleting any additional account and plug the internet cable back.

I cant see them loading anything if they dont have access, or is it that you cant prevent them access?

When I reset, it loses all the ISP settings. I don't know what they are (pppoe, static ip etc.) so I have no internet unless I let them load their settings back. When they do they also lock me out of the router.

I see.

I'm still a bit curious as to how you "let them load their settings".
Is it somehow via remote desktop, do you literary unplug the router and hand it to them for configuration, or are they using another method altogether?