When you install another Mcafee program not the same 1 as before ie Internet security instaead og Total protection you really need a clean install as per http://service.mcafee.com/FAQDocument.aspx?lc=1033&id=TS101331
Though I would have thought support would have tried that first.
That said to get a refund you need to be within a set time period 60 days for a new purchase 30 days for a renewal. At least I think that is it.
Customer service can refund you method of asking is here.
Contact the support staaff for your country