Overcharged

I am really unhappy with the service I received from one of your agents they dropped the call when I was still taking to them that is very rude considering I am a long time client it's really unacceptable. I called in before telling them I want to cancel 4G and get 5 G then one of your agents said I dont need to cancel they will make it an upgrade now I ask them why did they charge me when I told them that I want to cancel which is not fair o my side I can't be paying extra from something I told them to cancel please can you rectify this I am seriously unhappy