Poor service & lack of accountability

I took my vehicle in for a service and was informed that there was a recall and that Barloworld Toyota Kuilsrivier was going to replace the driver side airbag. After I received my vehicle back the hooter did not work anymore. I then took my vehicle in again to have it checked and was informed that the spiral cable on the steering wheel needed to be replaced. The cost - R7000. The problem I have is that everything was working fine before they replaced the airbag and after the replacement, it wasn’t working anymore. I contacted Toyota Customer Services to try and resolve this as I don’t think I should be liable for the cost of something that was working before they replaced the airbags. Toyota Customer Service contacted Barloworld Toyota Kuilsrivier and asked them about this and their reply was that they are not liable for the cost of the work they did as it was not anywhere near the spiral cable. The airbag and the spiral cable has a direct connection. Saying that the work they did is not anywhere near the part I have to pay for after their mistake is ridiculous. Just another company that is at fault and then pleads innocence.