Bad Attitude and Treatment from Milton

I am from a company called Selmac, which is a client of PolyOak Packaging. I would like to bring this to the attention of management at Polyoak Packaging regarding the bad treatment and attitude we get from one of the employees from Polyoak Packaging in Centurion. His name is Milton, on the 22/01/2018 we called Polyoak Packaging asking if they have water bottles and caps and he told us they don't have stock and when we asked when will they have stock he said he doesn't know. On the 23/01/2018 early in the morning we called again and he told us there is stock, after he realized that we calling from Selmac he told us that if he knew that it is us from Selmac he would have told us there are no bottles. We don't know why he is giving us this bad treatment while we are bringing money to Polyoak. Can you please address this issue as it will end up pushing us away and we look for alternative suppliers.