Refunding down payment; developer increased H&L TCP by 48% of the original and signed pre-selling price

Dear Attorney, I'd like to ask if it's my legal right to demand the developer of the house & lot I was purchasing to refund the down payment I have paid to them since January. I signed the Agreement upon reserving the unit last December 2021, but now, 7 months later, they said there will be an increase in the TCP (from 3.2M to 4.7M which is about 48% of the original TCP) because of inflation which I believe is really unfair because the reason I paid a reservation fee is to lock in the pre-selling price of the unit. Now I want to demand a refund of the 7 months (January to July) worth of equity I paid to them because there's no way I can afford the new TCP, but they are not responding to my message. I think it's a bait or a scam even, that they try to convince prospective buyers to reserve early supposedly to 'lock in' the price before the price increase, and then in the middle of equity installment, they'll announce a price increase. It's really unfair and inhuman. I understand that the reservation fee is non-refundable, but I still have the right to get the down payment back, don't I? Please help me with my arguments when I file a claim, because I am an OFW and it's already really hard to earn a living here but then these developers are becoming more and more creative in deceiving unsuspecting buyers. Please help me get my money back. Thank you so much in advance for your legal advice.