Hi There

I recently purchased a Sigma 10 -20mm Wide angle lens, and decided I would like to buy a Sigma lens hood for it. I bought one on eBay which was advertised as Sigma 10 -20mm clip on petal lens but when I received it I realised it was too big (90mm diameter as opposed to my lens diameter of 77mm) The seller said that he didn't accept returns, so my question is, which Sigma lens would this 90mm hood fit?. I want to resell it on eBay and provide all the info. I have searched around with Google and can't find this info. I also cant seem ti find the right Sigma hood(77mm) for my 10 -20mm apart from a couple on eBay in America which are rather expensive (I'm in UK). Any help and advice on this would be appreciated.