Does things without consulting the client

In August this year, my son in law Tertius Grobler had taken in his Kawasaki ZX400 to RCR Motorcycles, Bellville, Cape Town to provide him with a quote in repairing his bike. The salesperson still working there at the time advised him that they would provide him with a quote before repairing the bike. They never contacted him during the time and he phoned them advising him that they are still busy with the quote and after 3 weeks he phoned them and they let him know that the bike is ready for collection, (no contact or advising costs regarding repairs on the bike in the time standing there.) They had also done additional work not requested above the original quote asked for without permission, for example, the spark plugs that already replaced before the bike had gone to them, charged for petrol although they received the bike with 1/2 -tank petrol. Have a long history of two months and the bike still not right with another invoice after the owner promised repairs without cost. Now suddenly they do not work on 400 anymore. Have such allot to show here and say about how unhappy he is but Hello provides not enough space to prove it and everything wrong sinse bike was with them.