Buyer wants to file refunds under maceda law

Good Day. We have a house and lot mortgaged in a bank that we're trying to dispose. We found a very interested buyer who doesn't have the full amount at the time. We ended up making a contract with them allowing them to rent the place for 2yrs with the option to buy. Their monthly payment (rent) served as mortgage payment. Came end of the contract, they didn't have the money to pay off the entire amount so they decided they won't proceed with their purchase plan any longer. As per our contract, they cannot get any refund as it's considered rent. They told us that they are covered by Maceda Law, so they're entitled to half of their payments. Are we, as seller, required to pay them back per this law?

Maceda law is for bank financing / developers who is register at HLURB