Worst Plumbers

Had a problem with my Geyser, Geyser didn't heat the water. Called Best Plumbers - they send out a plumber, plumber checked and said that nothing is wrong with the Geyser, and called their electrician to come and have a look. we received an invoice from their electrician, with a call out and repair fee. We paid the invoice. Now I keep on getting calls from Amelia saying we never paid!!!! Now they come with a story that we are suppose to pay a call out fee for the plumber (who did nothing - and he called out his electrical department). And we have a call out fee that we paid from the electrical division . This is insane... as i called and said I dont know what is wrong and we don't have warm water. and we only received invoice, that was paid the same day that they fixed the geyser problem. Now they want us to pay an invoice that we never received and they have the nerve to ask if they can email it, and we can make arrangements to "pay them off" ? Seriously !!!! Pathetic!!! So in the end we must pay 2 call out fees ..... for 1 job done?