Bharat Sanchar Nigam [BSNL] — I will not received otp

My name is jaganathan. I have used a mobile it used sims name are bsnl (Sim2) and airtel (Sim1) bsnl no:[protected] the mobile number used in last four months (Approximate). This number used for many places (Ration, lpg, aathar...) but any service send for otp i will not received that time. I'm received for after 30 minutes. Spot time is use otp. What use after received otp. And many customers calling in my bsnl no:[protected] that time is not reachable or switch off the number. Many times this problem. I have live in chennai this area is not reachable? So i will recurce permanent solution.