Tired of Auto and General just *****ing from us

A few months ago i called for a geyser issue, they over charged me and I am dealing with the query still. Today my geyser started tripping already, I advised the lady that they were here a few weeks ago and we paid for the replacements of the parts, she said ok if the geyser needs to be replaced theres an excess of R3500, i said ok but I doubt it because it should still be under your warranty. They came here, did not replace the geyser but charged my partner an excess of R2450, no invoice to state what it was just the printed machine print, When i asked my partner he said he didnt understand what the guy was saying about the parts but they definitely did not replace the geyser. Please tell me why they charged us an excess for no replacement of geyser and did not tell me about it?