House purchase heartaches..please help!?

Hi there! My husband and I recently purchased a house and lot that is part of a compound of 4 houses(including ours). This compound used to belong to a single owner who initially rented out these 4 houses. We were one of the renters until last year when the owner decided to sell all 4 houses. WE loved the house and its location plus the compound has a common area (which is the driveway) wherein our kids can play with the neighbors' kids in a safe and secure environment. We bought the house we were renting . The other renters opted not to, so they left because the ones they rented eventually got sold. All houses were sold to different buyers except one(this one last house still belongs to the compound owner). Because this is a compound, when we arrived in this place the water supply setup was this: there is one water line from Maynilad that goes into the compound. This means the compound occupants pay its water bill ulatively based on the individual water meter reading that was placed in each household's home. There's one water pump that pumps the water into 2 overhead water tanks. One tank is for the use of the 2 houses on the left side of the compound, the other one goes into the other 2 houses on the right side of the compound. We are on the right side of the compound and the house which we shared the tank with was bought by a relative of the owner(which we will refer to as RELATIVES from hereon). Just a couple of months ago, there was already a feeler from the RELATIVES that the owner has given them the ownership of the tank including the pump and the water line from Maynilad. We were advised that we have to set up our own water supply because they would soon cut off the line from the tank to our house. It would cost a minimum of 80k to do this. This really devastated me. My question now is, is this legal? Don't we have equal right to the tank, water pump and line like the rest of the buyers of the compound?. Isn't it the original owner's responsibility to provide these basic necessities when we bought the house? By the way, the water tanks are erected on the common area which is the end of the driveway. We bought this house with an existing water supply and now it's being taken away from us! Should we stand our ground? As of the moment we don't have the means to install our own water supply. Please help!! I just want to know our rights to this if ever we have one. Thank you so much!! GOd bless...