I have nad this a couple of times over the past .
I have been buying from a couple of sellers over the years ,Instant payment after the purchase is confirmed.Sellers feedback says great buyer wish they were all like that A1 etc.
Then you have one item go missing ask about it and instantly you are treated like a criminal banned from buying anything from the seller when you go back into their site to purchase an item without any any explanation or message from the seller.
I have tried to find out why I was banned but no reply asked E Bay no reply just silence from everybody
I think that there should be a reconsilatory process run by E Bay even if it comes to nothing .
If blocked I think the seller should be made to explain why you were blocked especially when you have only made an enquiry
Over the years this has actually happened a couple of times Once on being sent the wrong article and recently enquiry about missing item
I realise sellers can do what they like with their items, but at least have the courtest to explain the whys and werefores of their decisions

G'day Ross, yeah, that sucks when that happens. haven't had too much problem myself with that but when it happened in the past, it's so annoying.
Agree, there should be some sort of platform on eBay for the seller to explain their decision to block buyers...
Good luck and Happy New Year mate.

Thanks Adrian yes it sucks especially when you are only enquiring about a missing item and not even jumping up and down about it, but as I say a seller can do what they like but that is rude especially if you have spent a lot of money with them previously ,
If I had a good recurring customer I would treat them as a favourite.
Anyway even if he comes back and allows me to buy again regarding whatever he has for sale he has lost me.
Happy New Year to you also .