Pricing and Warranty for Apple Accessories in Nigeria

An authorised apple retailer in Nigeria just informed me that my MacBook charger is not covered under my (still existing) warranty. And they tried to sell me the magsafe cables at over $100 as against official apple store price of $49. I have spent hours looking for an avenue to make an official complaint against them. There is no means to talk to apple support from Nigeria. How do I make sure that apple knows about this?

PS: It's iStore Ikeja City Mall