Is it permissible to unlock an internet device to use another company's card at a lower price, and is it permissible to offer this service to others for free?

It is not permissible to use the company's device for the services of other companies without its permission, as this infringes upon its rights. Muslims are bound by their conditions, and since the company does not permit this, it is obligatory to refrain from resorting to trickery to bypass its protection.