I sell clothes and shoes via instagram, found this supplier as he/she messaged me about her items. I made it clear from day one that I want exclusivity and that I want to be the sole distributor of her/his goods on my region.

Found out today that he/she is messaging my competitors around my area, that i get items from them. Told my suppliers that it’s a lose lose situation for them since i can sell 10x more than my competitors and giving them the same item that I have will just destroy my market which equals to less items that I will be buying from them.

What strategy should i use to make my supplier just sell goods to me?