Hi ameetzain !
This is not the only problem faced by you.....
You face problems with Nigerian buyers.
But i face with our Indian buyers.
I sell almost 60 items in a week.
Out of that, only 10 buyers are true buyers.
All other remaining ones are fraud.
With wrong contact details or they do not even care to reply.
This is the most negative point with eBay.
You can do one thing is, setup Buyer preferences.
In this section, you set constraints upto some level wherein you can avoid buyers like Buyers registered outside India canot bid on your products, Buyers with unpaid strike canot bid on your items, etc.....etc.....
Hope this information will by useful for you to some extent.
Thanks.
Pramukh Telecom.