[CAVEAT: I'm not an owner, so don't know the full details of previous arrangements for group aircraft I've been involved in!]
I would expect that you're paying to have space in a hangar, whether you use it or not is down to you (for instance, if you went down route for a month or two, would you hope for a rebate?). I don't view hangarage as being like a car park, where you just pay for the time that you're there - it's more like renting a house, where you pay for an agreed period of time and how / if you use it is your choice.
Obviously, if you have a different agreement with the owner of the hangar, then that would be judged on its own merits. Have you been at other places with other agreements?
Sorry if it seems a bit clinical / harsh, but I would think that any rebate on the hangar owners part would just be goodwill.