Harassment by nandini milk outlet employee in btm layout

On 14th june 012, I went to the nandini milk outlet in 16th main, btm layout second stage. I wanted to buy milk packets for rs.12.50. But I had only rs.20. The shopkeeper claimed he DID not have change but he was giving change to all other customers. I asked him atleast for a slip saying he owed me change(in the past, I've received such slips from the shop). He said he would do neither and started verbally abusing me. He threatened to physically assault me, all because I asked for change or a receipt. This kind of harassment is totally unacceptable and I would appreciate it if someone took action on this shopkeeper