Charged twice for the same work

I recently had my fibre installed by Fibrehoods(Vumatel). When installing the line they informed me that they will bury the line so the dogs would not be able to tamper with it. After a day the dogs had already uncovered the fibre and chewed into it. i informed Vumatel that it was poorly installed and i have now been quoted R1710.00 exclusive of VAT when the normal installation cost is R1710.00 inclusive of VAT. it is quite unfair to have to pay a second inflated installation fee for Fibrehoods to correct their own poor installation. I am happy to pay for a repair but to be charged such an inflated amount on top of the installation fee is ridiculous