Be careful from the buyer online thefts in Qatar living

I had added an advertisement in Qatar living a month before and I usually refreshed it on daily basis. One day I got an email from a buyer "keith sharon" and he introduced himself as a marine engineer working in Qatar and a native from Australia. He wanted to buy the item for his "in-law" who had recently been transferred to West Africa and he wanted to give him as a gift. He gave me his In law's address and which is located somewhere near Nigeria which is an African country. He asked my account details so he can transfer money including the postage charges to Nigeria. So I went with the parcel to Qpost and inquired about the postage charges and later I emailed him the total amount. Then in return I received an email from "[email protected]" which mentioned "HSBC Bank Qatar" and asking me to upload the receipt and tracking number of the postage so that the bank will verify it send me the money added by the buyer as soon as it receives the Qpost receipt and tracking number. But the email was actually a fraud one. Later I told the buyer that I don't trust the email which I had received so I need to speak with him personally and asked for his number and he told me that he is a marine engineer and he cannot make or receive calls. Then I understood that it was all drama. I never had any proof of him other than the email ID. If I had sent him the parcel then I wont hear from him again. So any advise on this issue will be helpful. I just want to highlight the things which can happen to anyone and some people may even get robbed thinking the deal is genuine. Can any one tell me where to report cyber crime in Qatar.