Rude and belligerent upgrade agent trying to hard close customers

I just received a call from Vodacom Upgrades tel: *** at 17:33 telling me that my 36 contract which is 1 year old requires an upgrade in order to keep my discount that was offered to me for 36 months. The agent agent was argumentative and when he spoke over me I told him that my lips are still moving and he will wait until I am finished. His response was that and I quote"You are not my buddy, you will not talk to me like that!" He continued to talk over me resulting in me losing my temper, he remained belligerent. This kind of behaviour is unacceptable and I demand management to contact me.