As far as my perception goes, the gold standard for measuring the service quality is SERVQUAL Model, developed by Parasuraman and Zeithmal. This is more than sufficient for measuring the service quality.

Thank you sir ,actually we have to choose another model other than SERVQUAL , another model on service quality

Following answer .

Other models than SERVQUAL for service quality ?

SERVQUAL cannot really 'measure' service quality. Quality of service is subjective, determined by the receiver. Therefor its measurement should be based on a measure of customer perception. A 10.000 feet definition would be Q=E-P, quality of service is expected service minus perceived service. Determine key result indicators for both, and do the math. A negative outcome reflects a negative perception, etc.

Thank you sir Jan van Bon