Different HSN code and GST Rate on Sale and Purchase

If there is a situation where i have been billed for an item by my seller under wrong HSN and GST rate , say 18% with HS coder 1234

The item however actually falls under HS code 4567 and gst rate 12 or 5 or 0 % ..

 Then do i have to sell under the right HSN code or i will have to sell under the same HSN code and rate as purchased