neha2000,
Firstly please do not send your request to FBI using a local post office. It is too risky as you have taken trouble in getting your fingerprints and bank draft. FBI takes approx 8 - 12 weeks to provide you with the PCC. If you send it with a local post office, you will need a few more weeks for it to be delivered and you can't track it.
I suggest you send it with a courier company, this way you can track it online to be sure it has reached the right place.
For FBI to return, they normally send it via their local post. But this is not a safe option as it could get lost in post and you do not want this to happen.
If you are working for a company and if your company has an account with an international courier company, then use them to get your document back. You can schedule a pick up (if your company has an account) where the courier company will pick up your document from FBI and have it delivered to you in Kuwait. You will pay the charges on delivey in Kuwait. They charge more to pick up the document than to have it sent. However, you must send a cover letter to FBI telling them not to mail your document and to inform you once it is ready. You should also tell them that you will have it picked up through a courier company.
I live in Dubai and I did exactly the above using the Aramex courier company. I paid AED 105 to have it delivered to FBI and AED 210 to have it picked up. As per my instructions, FBI contacted me after 8 weeks on my e-mail address and informed me it was ready. I then arranged to have it picked up.
If you company does not have a courier account, you can open one with any courier company. I am not sure on the procedure of opening it, but a friend of mine opened an account with Fedex and had the FBI PCC picked up.
As this document is very important do not risk it.
All the best !