HDFC Bank — Reimbursement of tests undergone

Address: 380008

We are a running a Diagnostic Centre and do checkups for clients of HDFC Life under agreement and receive payment on submitting test reports. We have not received payment of about 24 clients for whom various tests were done in 2015.
Inspite of sending reminders through mail and also through telephone, they are not responding nor paying us our due.
The list of clients has been sent to them for more than four occassions. They are not even picking up phone, forget about making our payme
Deputy Manager\Medical\HDFC LIfe based at Shivalik Plaza, Ahmedabad Office is the coordinating person with their account department.
This attitude is totally unacceptable by such a Company.