Poor service

My Cell C contract is ending in July 2023 so on 1 June 2023 I called retentions department for a cancelation fee and Monica said it was R378.79. When I received my statement I got puzzled and called agin today just to confirm the amount as Monica said it would be that amount until 30 June 2023 but to my surprise the cancelation fee is now R783.79. I'm sick and tired of the poor service rendered by this cellular network hence I'm even canceling my contract in the first place. Then when they call for a resolution it's just an old tired explanation