Rera can only enforce the rules if they are informed of an infringement, many people don't make an official complaint to Rera for some unknown reason !!, in the past some agents were taking reservation deposits, issuing their own reservation receipt and then negotiating with the developers. The only way to avoid this is to insist that you see the agreement between the agent and the developer ( in this case Abyaar) authorizing the agent to sell the unit he says he is. And then insisting on a written time limit for the developers reservation receipt to be issued or full money has to be returned.
The reservation deposit has then to be handed over to the developer and placed in escrow, again insist on knowing the escrow details of the developer. In some cases this has not been done.
In the case of Pier 8 construction is extremely delayed so insist on a written completion date, imo its going to be early 2017 before handover and that's if they get restarted within the next month which is also questionable.