Khetra Mohan shop Bagmari Bajar - Rude unethical behaviour of a shop owner

The behaviour of the shopowner is shocking❗I bought a wood cutter this morning(**/**) and he charged Rs *** though the product had no price tag.I paid the amount duly.As I raised a proposal of burgain a little he started hoarse argument and also snatched the product from me.How can he said to have been fixed price when the product had no price tag??Again he used some slang words to me as insulting me.