Always request your old parts if new one installed

Took vehicle form service out of 4 faults found one was telephone thru to me. That's the fuel line having hairline cracks.I requested a price and then agreed to have this replaced provided the old is give back to me. 10 minutes later received called from unqualified service advisor Peter that there is no need for replacement.this was fishy and remembered Carte Blanche investigation as to how new parts are drawn on your car job card and then fitted on private repair that service advisor and mechanic do after hours.address this with service manager who says this's not the case as he has confidences in this staff and he could Peter thru a polygraph test. I challenged him on this. He failed to do so. He knew his staff member will fail hands down. Address this with division director who refer this to dealer principle Ravi . This guy was rude and abrupt to me and angered me. I lost my cool with guy and he decided to tell me take my car to another dealership as he doesn't require our business. Address this vw South Africa they say that they can't interfere with their marketing agent business. Dp also mention that service advisor was saving me money who is he to judge my affordabilit