GST on maintenance charges on society flat

There are 240 flats in our society KLJ Platinum Plus, Sector – 77, Faridabad out of which more than 160 took over possession and staying. The flat buyers have registered RWA in the name of RWA KLJ Platinum Plus D1 to D4, Sector – 77, Faridabad. For the maintenance (security, Lift, Fire hydrant system, water, common area housing keeping, gardening, sewage system etc) of the society the Developer (KLJ Developer Pvt Ltd) has engaged one third party (DM Reality Pvt Ltd - a sister concern of KLJ Developer ) and made a maintenance agreement of DM Reality with individual flat buyer. According the initial maintenance agreement at the time of possession (year 2015) with DM Reality first year they charged Rs.2.15/- per sqft (monthly bill 979 sqftX2.15= Rs.2015/-) to the flat buyer. Next year onward the charges was suppose to be decided on the basis of cost of actual expenses incurred in previous year + 20% over head. However in 2016 since DM Reality did not able to provide the detail of cost of actual expenses of previous year (duly audited) they made one agreement with RWA to charge Rs.2.05/ sqft towards maintenance of the society to the flat flat buyer. Our query is - since the society has registered RWA and all the maintenance charges with DM Reality is being decided by RWA, DM Reality is providing services to the flat buyer of the whole society and sending bill for maintenance charges to the individual flat buyer with GST, whether the exemption of GST on maintenance charges up to Rs.5000/- p.m. is applicable when the maintenance bill per month is around Rs.2000/-.