car workshop in SG- slowness and delays

we left our car at a car workshop (located in the Carros Centre) only for them to spend one month to diagnose the issue, and to date they are still unable to commit on the timeline required to fix it. due to the multiple delays and slowness in replies, we’ve decided to move the car to another car workshop.

would appreciate if anyone can share if there’s any consumer protection for car owners who believe the workshop might have taken an unreasonably long time just to diagnose? is there any action we could consider taking against the workshop?

grateful for any advice on this matter. thanks!