Multiple buying options on my own product

Hello, i am fairly new to Amazon and need some help and apologies from now if this topic has already been covered in another thread (i couldnt find anything)

How is it possible for someone else to be selling my own product and trying to price battle me by constantly selling at a cheaper price even if its 1 penny less? on my listing it shows 2 buying options and shows “sold by” the store name of the individual if they are priced cheaper than me.
this is my brand and my product so how this is allowed is beyond me.

appreciate the help