They retrospectively raised the project cost by 41%

I was given a quote for the installation of an EV charger, based on Amptex's questions, which I answered accurately. Two days after the job was complete, I received an invoice for 41% higher than the agreed amount. At no point did Amptex let me know that a revised quote was needed because the installers thought a new route for the cable was the better choice, as is required by law. I was not given the option to approve or decline the revised cost (I would have declined) and only became aware of it when slapped with the bigger bill two days later. Furthermore, the technicians (very dangerously) put the wrong labels on the sub DB board (they labelled a switch flicking between Eskom supply and my inverter supply the wrong way around). The installers were friendly and the operations team was initially, but that doesn't make up for the obscure billing and dangerous labelling (which I had to figure out and fix myself).