Concern for overall quality of assessments provided

I recently took my car in for a service and was presented with a very large quotation for multiple issues. Less than a week later, my car wouldn’t start — the battery was found to be loose, something that should have been properly secured or identified during the service. No battery issue was raised when collecting my car from the service and the issue only arose (within 1 week of service) after the vehicle was collected. This experience has raised serious concerns about the thoroughness, accuracy, and overall quality of the assessment provided.