Mr.Nayak,
Greetings of the day!
I would suggest that you should implement the following strategy in your corporate office-
1) Incorporate or implement CUG (Corporate User Group) post paid plan which is best suit for your organisation.
Call various teleservice provider e.g Vodafone, Airtel, Reliance, BSNL etc. for getting a best suitable offer from them.
Study their comparative offer and network services.
Within the CUG , all user gets freebees services within the same zone/circle. Example-WB Zone, within the West Bengal circle CUG user can talk to each other with free of cost.That means they do not require to talk to each other through land line services.It reduces corporate tele bills drastically.
2) Fixed the mobile reimbursement limit based on business requirement and employee grade.
Distribute the CIRCULAR regarding CUG Offer among your employees and its limit of use and reimbursement procedure.
Regards,
A.Rahaman