Pathetic service

I lost my phone on Sunday,and I cannot blacklist my phone.I just spoke to the lady who said is Xolile she was rude and drop the call on me said the information is not corresponding I have my box phone with me giving them all the information, they are promoting ****s to get away with *****ing our things I'm very upset I like this lnetwork but the Service in call centres is pathetic..I want my phone blacklisted.i paid so much for phone it's 6moths old galaxy A12