I currently pay for internet only, if i get thier phone service in as well i am entitkled to a free stb for bog standard tv,which i would assume should be ready for me to recieve if i want, premium channels.
Simply check if your signal is too strong or too weak for your box.
If the signal is too strong use an adjustable attenuator at the box line and if the signal is too weak use an booster.
If you need an booster and the premium channels are broadcasted in the 300 mhz range in your area a argos booster is not so good.