02. *The user has one SIM on mobile data & other SIM (both different telcos) not active on mobile data & he tries to register using the sim which is not on mobile data, punching the MSISDN active on mobile data & we are live with only one telco i.e. the one with active mobile data. as per my understanding, we will return a false verification to the SP & they would be charged for the same. Please clarify.

Let me try to rephrase your scenario in a more simple form: 

2 SIM cards in the phone – from 2 different telecoms (usual case as they are utilizing different Telco promotions in the market): 

1 SIM card with Active Mobile Data session, other SIM with NO DATA enabled, used only for voice and SMS

Let’s assume we have the full country coverage 

– If the user enters the MSISDN (phone number) of the SIM card with Mobile Data active session (which client will instruct the user on the App screen), then NO PROBLEM, by calling IPification API they will successfully verify the entered Mobile Number and will receive the correct Mobile ID from a network triplet connected to that Mobile Data SIM card. 

– If the user enters the MSISDN of the other SIM card which is not connected to Mobile Data (despite client instructions on the App screen), then by calling IPification API , client will receive FALSE in the reply to Phone Number verification (because phone number entered is not matched to the one we have on Telecom side via Data session) but client will also receive the Mobile ID hash (connected to the network triplet of the other SIM card connected to Data session). 

In the latter case, since app developers know if the current device has multiple SIMs, they can assume if they received the FALSE in a response from our end on the Phone Number matching, to use SMS as a fallback to send OTP to that MSISDN user entered in the first place and to still manage to verify him/her in this way.