I dislike telephone communication in general compared to face-to-face interaction. I am not interested to communicate with anybody by mobile phone for a socialising or business purpose. I work from home now and am near-constantly reachable on the home land-line telephone number.
If I am out, nobody needs to reach me urgently anyway, except my family. So the only mobile phone I use is a "family number" for me to maintain contact with my parents and sister. This number is linked as a 'twin number' with my father's mobile under a "family sharing plan" offered by the telecom provider, and is not meant to be given to anyone else. The point is that the family mobile number is not the same as a personal mobile number because it is not even my phone or my number, and it could be used by any member of the family.
I really don't have a personal mobile number, and it's mainly because I had several negative experiences with mobile phones when I used to be a high-ranking public health official in city administration for a 2 year period in 2010-12. I am not active on any social media except Stack Exchange which is apparently not a social media, and prefer to get communications by email rather than on a mobile.
However it seems to be a new element of social culture here in India that whenever one meets an old friend/ acquaintance or meets someone new in a professional or personal capacity, they end up asking for your mobile number. It is real-world social "networking." This happens to me routinely and I have struggled to give these people a good answer. People look amazed, disbelieving and hurt when I say that I don't have a mobile number. They want to know why. When I happened to meet an old classmate after several years last Sunday at the supermarket, this problem recurred:
After speaking with me for few minutes,
Friend concludes: OK I'll keep in touch. What's your Whatsapp number?
Me: you know my personality; I am not on social media.
Friend: still you must be having a mobile number...
Me: I don't have a mobile number. You can reach me anytime at my home number which you already know.
Friend: I seen a mobile phone in your pocket.
Me: That's my mother's phone. You can reach me on that number too...
Friend: I don't want your mother's mobile number.
Me: (smiles stupidly.)
Friend (disbelieving): what? You really don't have a mobile number? Everyone has a mobile number. Why you don't have?
Me (invents a weak excuse): I am changing my mobile number. The new number will be obtained in a few days. Meanwhile you can reach me anytime at my home number.
Freind: ok, be sure to send me your new number when you get it.
These people often look hurt when I say that I don't have a mobile number, as if they suspect me of being unwilling to share my mobile number with them. Some of them ask why, but I am not comfortable with discussing my reasons with these people. So I am forced to invent weak excuses.
It's a fact that I am extremely introverted and don't want casual telephonic contact with friends, relatives & acquaintances. So my aim is to channel all calls to the one home based land-line telephone number (or, alternatively, my mother's phone) so that I am actually reachable but people will use it only for a genuine purpose. However I find that it is not enough for a person to be reachable on some telephone: sharing one's personal mobile number has acquired a whole lot of social and interpersonal connotations so that not having a mobile number is viewed as unbelievable and downright counter-cultural in this age of instant communication.
If I meet this friend again a few weeks later he is sure to ask me again for my mobile number. How do I convincingly convey to friends and acquaintances that I don't have a mobile number of my own, without going into my personal reasons which I do not want to discuss with these persons?
honest yet blunt responses like "this phone number is only for family members", "I dislike phone communication" and "I don't give anybody my mobile number" are considered unfriendly in Indian culture unless you give them a full and detailed explanation of the reasons, which I don't want to get into in these cases.
As clarified by a very constructive comment from user @Cascabel, what I am really seeking to convey convincingly to friends and acquaintances is that I am not available for real-time voice-calling and WhatsApp based communication via a mobile phone, but saying that explicitly to them would be considered very unfriendly here.
May I also clarify that I am not asking for 'convincing excuses' as some members might have misunderstood, but seeking a convincing interpersonal approach to the situation.