Pay advance for two wheeler by connecting online Facebook

Hello Sir or madam, I get connected through facebook market place for buying two wheeler (Ather 450x) then share both contacts and wapp then meet personal as per given address. As per see pics and check condition then test ride there are 4 other people sitting in that place and discussed with RC Book, Insurance & pending warranty. Among the 4 person one person has told me that there are 5 years of warranty on battery so no any problems you after that time. Now all this discussion & we finalised that vehicle to purchase and give Rs. 2000 as advance in cash and that person i have connected give RC Book Photo & 2000 as advance on my wapp no. I take 2 - 3 days time for rest money payments and take vehicle. Now as per the warranty of 5 years that person said i check with RC Book but not getting proper reply so called that person to give me Invoice Copy, Insurance & Model Number for more inquiry. As per that documents provided by that person the company customer executive for only 3 years or 30000 km whichever is earlier. I called that person for this situation and request that before finalised the warranty of 5 years on battery its not valid, now as per this documents i cannot pay as per agreed amount & offer new amount. Then after sometimes that person called me and said we have not any discussion of 5 years of warranty, if you not pay rest amount we not refund your advance so forgive. Me & my mother also request on call this condition but that both person not proper replay of refuse to pay advance after finalised deal. Then after that they not agreed i said also that if any one can give the same or more amount you give me my advance after 7 - 10 days but they not give proper answer after that times. I wapp also for this & request for this to solve & pay advance or do negotiate i agreed to pay you. But after 2 - 3 days i wapp so many times for resolve but said that one another person had finalised with others and sell that vehicle. now today when i go personally with my sister i saw that vehicle at that place and said that in evening that personal take vehicle then i will pay advenc after that another person give me.