MusicDirect

I was wondering if someone can explain if it is appropriate for a vendor to charge buyers the sales tax rate where the vendor is located instead of the sales tax rate where the purchaser is located, for an online purchase? MusicDirect is located in Chicago where the sales tax rate is 10.25%. I live in Illinois but not in Chicago where the sales tax rate is 6.25%. MusicDirect persists on charging me 10.25% when Amazon, eBay and other vendors charge me 6.25%. They have told me that they charge me 10.25% because the have “a physical nexus to Chicago”. Well I do not. Using MusicDirect’s logic Upscale Audio should be charging me California sales tax, which they do not. Anyone care to explain to me if MusicDirect is correct in their practice and why? Thanks.