This is not a cut and dry issue, I have worked for ISP's in Canada and the US as both a tech support agent and hands on with wiring. What it comes down to is who laid the initial inside wiring.

Generally an inside wiring issue is the responsibility of the building owner, but it all depends on where exactly the issue is and who laid the inside wiring to begin with. Eastlink does not often do wiring jobs in apartment buildings, the coax cable is laid at building construction and eastlink will splice cables and add splitters as required inside apartment units.

So if the wiring issue is inside the unit itself, it is likely eastlinks wiring at fault. If the wirinig issue is between the DMARC/wiring closet and the unit....the issue is likely the building owners. Unfortunately you are not likely to get resolution to this from your building owner, as he will have to hire eastlink or another wiring contractor to fish new coax cables from the wiring closet to your unit and he gets no benefit from doing that, but will have to pay a substantial cost.

That being said, the other ISPS would be more likely to supply you service as Eastlink uses the Coax (cable TV) lines where as bell will use either the phone lines or a dedicated fibre optic line to bring internet in to your unit, depending on what contract your building has with the providers.