Chargeback

Not really sure if anyone else ever had this issue but I recently bought some lego figures from a pretty well known seller who has a 4.9 rating on November 9th. Its now the 25th. The status says shipping because he changed it to that the day after I bought it but USPS says it never recieved the item in the tracking. Its just been stuck in the same spot. I tried contacting him many times and he only responded once a week ago saying he had a problem with the post office and would fix it in that week which he never did. I also tried contacting support but no response in 3 days. Should I just chargeback and risk the ban? I feel like this is abnormally long and support is no help.