Charging extra for heat section 8

[Andrea Galvez]

Hello everyone, 

My building has only 1 boiler for all units, therefore I am the one paying for heat. In my lease, I said I would provide heat up to 65 degrees, and any temperature higher will be responsability of the tenants through other electric sources (like space heaters). This went through section 8, and the tenant was ok about it, so she moved in. Next day, she was complaining that the temperature was too low for her, and she couldnt heat the whole unit with space heaters (its a 1200sq apartment with basement), so we verbally agreed to provide whatever heat she wanted for an extra $100. Thats what we did during april and may, but we didnt notify of this to section 8. Now, the tenant has to pay for something that she damaged and shes trying to get away by saying she is going to tell section 8 I charged extra for heat. 

So my questions are: (1) Did I do something wrong by charging that extra amount to her, since she requested and came up with that solution?
                                       (2) Can I get in trouble with section 8 because of that?  
                                       (3) Is this somehow iligal?

Thank you!