I dont know about other countries, carriers or contracts. But my contract clearly stated that my phone provider can cancel the account anytime without prior notice if they think that is necessary. Its a typical piece of text you find in many service based business contracts. I dont claim to know what exactly this means, but it surely is a difference to having to sue me for a valid reason to be allowed to take over my domain. A process that not only takes a while but also has several prior warnings.

Sure it is not _mine_ ether. But it is more mine than a phone number ever will be.

Edit:// I tried to look it up, except trademark stuff (and even then its not easy) i dont see any reason a domain could be taken away from the renter while beeing paid for.