Heating Contractor Who Takes Payments?

We brought this house in 2014. The heating system only works in part of the long ranch style home. We found out last year that some of the vents in the attic are connected with gray tape. Some of vents are not connected at all.

We have blocked off part of the house because we have no heat in that area. The other part that we really live in we use infrared heaters to help keep us warm. We also found out that the floors throughout the house under the laminated flooring are concrete. With the bills we have, and the house payment that has gone up three times since moving here, we can not afford to have someone come in to repair the heating system. Also the furnance is not large enough to cover the length of the house.

Is there a company that will come out to do the work and we can set up some kind of payment on a monthly basis until it is paid in full? Thanks for your help!