So starting off the first step for training the dog for using the invisible fence is to set it to beep only (regular settings beep for a few seconds then give a shock). After my dad set up the electrical fence he decided to test it on the dog, then my brother did the same thing the next day. With neither of them reading the book, the dog got shocked twice for pretty much no reason. Now he is so scared of the beep, as he hears it he sprints for the house tail under him and ears down. I've been put in charge of training the dog and I have no idea how to fix this. Please help.

in case this helps the dog is a 8 month Pitbull Boxer mix.