Item repaired without approval from client

On 4 March 2022 I took my engagement ring in to my local Sterns branch, Vredenburg 7380, West Coast. There was a small diamond missing from my ring, so I took my ring to Sterns and asked what it will cost to get repaired. The ladies there said that they have to book my ring in and send it away to get a quote as they couldn't give me an amount in store. On 14 March 2022 I received the following sms, "Sterns Repair Ref RE**** quote: Total cost: R****. To accept or reject the quote within 7 days click here https://mycustomer.tfg.co.za/Repair/Quote/accept?repairNumber=RE*** or visit Stn Vredenburg. Agree to T&C https://ww****g.co.za/terms-and-conditions to accept." Directly after the above sms, I receiving another one,"Comfirmation: Your have accepted the Sterns Repair quote. Ref RE*****. We will let you know when the repair is ready for collection at Stn Vredenburg. https://ww****g.co.za/contact-us" I did not even have a chance to accept or reject the quote. I immediately contacted the the lady at Sterns Vredenburg, and asked what is going on. She said that the ring has already been repaired. I was livid as I asked for a quote and not to get it repaired. Now I have to pay for THEIR incompetence. They accepted fault and brought the amount down, but I STILL have to pay a fee. This is UNACCEPTABLE