Company frequencies are used for contact with either the airlines ops or maintenance departments or the handling agents. Ops are called with enroute messages or other operational issues such as diversions (if you are close enough to talk to them about it) and maintenance for inflight tech problems.
It is nice when inbound flights call up the handling agents with eta's and special requests as not all messages sent are accurate, and some aren't sent at all. For all those crew that don't call up, and I'm sure most handling agents have one or two airlines that don't, don't start ranting and raving at us if it takes half an hour for wheelchair passengers to be collected when we didn't know about them or there is no one to meet you because the eta on the movement signal was seriously wrong.