Uniconnect Sim — Very rude customer staff

I had bought a Uniconnect sim for Malaysia and before flying out I had certain questions regarding recharging and currency to ask so when I called their service centre, Rahul who attended my call was the rudest staff I believe. Instead of helping me with answers he said that I visit the website first and then see if I need answers. This kind of service is totally unacceptable especially when we have paid for a service. Now if someone can tell me, how do I cancel this sim totally?? I do not wish to use uniconnect and it's services at all.