OK going by what I remember from the gemara (my memory is so sketchy on this so…)
If a squatter stays in a field that you would pay rent for, and they planned to charge for, the squatter is gaining and the owner is losing and the squatter is liable.
To me, that means since you WOULD pay for internet services, and the cable company would charge you, its against halacha. But I don’t know if thats how we pasken.
Honestly, I’ve done it in the past but I don’t think its right. Legal, possible, probably not ok according to halacha (ask a Rabbi) but it doesnt mean its right either.