We are renting and the landlord will not fix the heat problem.anything we can do?

we live in a 3 bedroom 2 bath town home in mid michigan...our place is way to freekin' hot and the manager/owner won't do anything about it...the place has 6 units and the heat is run to the apartments with an old boiler system that feeds the heat through the radiators in the units...none of the units have a way to control the heat...we are the hottest unit because we are the 1st unit and the boiler is directly under us...the radiators are so hot they are scalding to the touch...right now it is 6:20 a.m...it is 85 in the living room...it was 84 in our bedroom upstairs...it is 88 in the daughters room...(we have bought little thermometers to check)...we put the thermometers in the middle of the rooms so they aren't directly heated by being too close to a radiator...it is just unbearable in here!...we have tried having the doors and windows open and it will cool things down...(of course it will when it is 4 degrees out!)...the other night we had our sliding gl door open to our master bedroom and it was still 79 degrees in there with the temperature in the low single digits...the manager has had a maintence guy come over a couple of times and he "pretends" to "adjust" the radiators with a wrench...it does no good at all...there are no knobs on the radiators where we can adjust them at all...i emailed the owner asking for knobs...we were told that the people that lived here before stole the knobs and they were not going to replace them...aren't deposits used to cover silly stuff like that...i ured him that we would not steal them!...lol...unreal...ok...what can we do to get this place livable?...opening the windows and letting the cold air has given our daughter 2 ear and throught infections this winter that she has never had before...what can i do to get the landlord to fix this problem?...i appreciate any insight or advice...thank you...