Whenever an application is submitted in CIDCO for transfer, it is allotted a CFC Number (Serial Number). According to Anti-Corruption laws, even if a govt officer gives out of turn facility (Preferential treatment) to someone or favors someone for quicker processing of files out of turn and not according to the serial number (Provided there is no objection or issue raised with the file or application) it is considered as CORRUPTION.
So if you are being made to run around by CIDCO officers since you are not paying them a bribe and you are 100% sure about your documents being in order, you can complain about out of turn favors to anyone who submitted his documents after you but got his CIDCO NOC before you.
If you know for sure that somebody who submitted his application after yours but got his NOC before you, its considered as CORRUPTION under the Prevention of Corruption Act.
You can also file an online RTI asking for the serial numbers of Applications submitted to CIDCO for any particular month and their clearance date. This will give you an accurate picture of whose application got cleared out of turn. You can file an online RTI from the comfort of your home here
If the number after your number (or two) shows that the NOC has been issued, you have your evidence needed for the complaint. They will have to investigate the movement of your application from the time it was submitted. Every movement of every file at every step in CIDCO is recorded in the File movement Register (peon register) and it is very difficult (impossible) to destroy this record.
Almost every CIDCO officer will be caught for corruption if this method is deployed by any citizen.
You can also complain online using the same logic at this link If you do not have an account you can created one by clicking on the Register New link. Once you make your complaint, you can also track it online.
Although it cannot be assured that your complain online will be acted upon. Always file a written complaint and take an acknowledgement from the Vigilance Dept on the xerox along with the date and time. Even though the Vigilance Dept itself is a big question mark, its worth giving a shot.
If you are worried about complaining while your file is under process, you can also complain once you get your CIDCO NOC in hand.