Not heard of them myself - what's the web address? Is it http://www.ioffer.com/, which looks a bit like ebay?
There's some reviews of that company/site on Amazon which seems to suggest it is legit (although maybe not the sellers!), it gets very mixed ratings! http://www.amazon.com/iOffer-com/dp/B00006EMSL
I've just had a browse of the ioffer site and it does look like it's full of knock-off and fake good from people with dubious reputations - perhaps one to avoid!