If you are renting a property or just moved in, and the reception is no good there is not much point in ringing an installer. The best thing to do is call the agency (or owner if private rental) first, and report the fault. The agency most likely is not going to refund you if you were to pay for repairs.
Many agencies have their preferred installers and the guy you call out may not get a “look in” anyway and could charge you for calling out. I have had this happen to me, and I’ve had it the other way around, where I’ve got the job as I was the agency’s preferred installer.
Also it is not unreasonable for an installer to charge you if it is your equipment, you’re connecting to the wrong socket or a tuning issue with your TV. I now advise tenants of this, and most of them are quite abrupt about paying for anything. I had a tenant recently cancel my call-out because I told him he may be charged. I had another tenant move from Sydney and expect his TV to magically work in Newcastle. I find it quite amazing that some tenants expect things fixed for nothing when the fault may not be with what is supplied at the property they are renting.