How much it cost time chain chai I audiq7 2007

What is your question?

I got fixed yellow light sign on the dash board of my Audi Q 7 2007 Model. Took to the repair shop They fuel sensors but even that engine light did not go then they changed the fuel pump even after light is still on now they say time belt to be replaced which they say will cost about $4500. My question is whether whatever they did is right . Mileage on my car is 117250. Other question whether I can continue drive drive locally or it will have impact on other parts of the vehicle also car gives tik tik Noise under the hood. Thanks