Do Not Respond to 'suspicious' ISD missed calls :BSNL
If you are a BSNL mobile user than you need to be careful when calling back on the missed calls you get from unknown numbers. If you get a call from a number that looks suspicious or it starts with +263 and +960 than do not call back, because if you do so than you will be charged a amount of Rs. 50 per minute. This is kind of scam that's being going on and the frequency of such calls has increased recently. BSNL has been getting complaints regarding these dubious missed calls from quite some time now and that is why they have officially came out to warn its users to stay away from calling back on those numbers.
This not the first time that mobile users from India has got such calls. Previously, Vodafone users had complained about getting missed calls from dubious International numbers and being charged heavily when they called back. This has also happened with Airtel users too (including me). I got a call from some big looking ISD number and at the first sight it looked suspicious to me. So, if you get a call from any unknown ISD number than refrain from calling back.