Is a 419 scam, NCAA website addresses this type of scam, but as yet doesn't name DYNO AVIATION. Same type as others using this telephone number. Note their website was established on 17 Nov 2012...
Do not respond to these people, and do not give information to them. Do not give them money or credit card details. Do not give them oxygen.
The African forum has a discussion on them, and their telephone number comes up with numerous 419 scams. Apparently the scams do not pay enough for new numbers, or they are that confident in the gullibility of the public they don't see an issue.