It is your right to have your vehicle's damage estimated and repaired at the collision shop of your choice
The Insurance Act: Market conduct Regulation requires that if an insurance company recommends that you have a particular shop estimate your claim or provide repairs, the insurance company must give you written notice of your rights to have your repairs estimated and completed by the shop of your choice.
However, the insurance company may, by giving you formal notice in writing, assume complete control fo the repair process and have the vehicle repaired where they choose. Insurance companies very rarely exercise their right to undertake repairs; since by doing so they assume final responsibility for a satisfactory repair job.
When you select a shop, the responsibility for a satisfactory repair job rests, finally, with you. Any dispute about the quality of the repair or the collision shop's guarantee or warranty is a contractual matter between you and the collision shop.
When an insurance company states or implies that they guarantee repairs if you take your vehicle to a shop they choose, ask about that guarantee. Ask to see the written guarantee. Find out: Who sets the repair standards (you, the shop, or the insurer)? Who decides whether a repair has been properly completed (you or the insurer)? If you are unsatisfied with the repair, who will re-do the work? Often, an insurance company's guarantee is actually the shop's guarantee and the responsibility for a satisfactory repair job will remain a contractual matter between you and the shop - Just as if you had chosen the shop. So, it's in your best interest to choose a collision shop carefully!
Once you have chosen a collision shop advise your insurance company.