noise after maintenance

I took my car to Big O Tire to do a maintenance, after inspection, the technician suggested me to do a major maintenance and replace 4 brakes, I accepted the suggestion and costs me $1000, and after 4 hours waitting, I found there is a rattle noise from back left wheel of my car. I drove back and the technician heard the noise as well, he checked the rear wheels and told me it is adjustment problem, it should be ok after 15-30 miles drive. I tried more than 30 miles but still noise. I had to drive back to them but this time the manager of the store told me it is problem of struts and shocks, asked me to pay another $721 to replace them. My questions are:
1. before doing the maintenance and replacement, no any noisy, how come thing was getting worse after maintenance? they said it is coincidence. 2. should I replace structs or not? they said if I want to remove the noise, I have to replace struts

Thanks for any suggestion and concerns.

BTW: donot go to Big O Tires to do services. Bad