Car Parking

In my society (total 9 building constructed in 1996) (separate societies formed in 2006 for each building) around 28 people are parking their vehicles in Open Car Parking Space (which is common for all buildings/societies) but only around 18 were asked to pay for car parking (Rest 10 People are not paying & they say builder has allotted them open car parking space) when i asked committee of the Society that i want a copy of builders letters in which builder has allotted car parking space (Strangely committee say that we have seen their letters by eyes, but are not demanding a copy of these letters from them) can i demand photo copies of these letters from the society as i doubt about the genuineness of these letters. if any member gives an unregistered letter of the builder & if it is fake (not actually issued by Builder) then will it be treated as Invalid (Letter wont stand in court of law) or Illegal (such Person giving false letters can be prosecuted & sent to jail) What can i do in such cases, what i want everything should be legal & Transparent what will happen in future if society go for conveyance (will the members who claim that parking were allotted to them by builders will continue to rule that parking space & paying noting to society) Please kindly advice me Thanks & Regards Ritu, (Pune)