How to organize mailing by phone numbers?

Question

Marketing

Dear colleagues!
Given: database with names and phone numbers of clients (<10k).
Problem: a mailing list is required, which could be carried out via instant messengers and as a result of which the recipient could quickly contact the sender.
I was thinking about:
• groups, but how can you get people there? In addition, part in the telegram, part in Viber, part don’t understand where. How to catch them all?
• SMS mailing list. But: old-fashioned, spammy and feedback is problematic.
• mailing through services. But: the problem with feedback and how to send a message to people who have telegrams, but no viber? And vice versa. And yes, it's bloody.
• chat bots. Everything is the same: you won’t drive, you won’t find out in which messengers who is sitting and the word “bot” can scare away.
• handles. There are no comments here.
I would like to know your experience in solving such dilemmas, perhaps there are some solutions out of the box (in any CRM, for example) or ready-made services.
All dankeshun for the answers!

Answer 1

This is now called cascading mailings, but I must say right away that the result will be very disappointing. SMS mailing will not suit you at all, because
a) you cannot send response messages to alphabetic numbers, and it is problematic to send from federal numbers
b) you most likely do not have consent to SMS mailing, so the base, consider it dead.
Messengers remain, but there is a lot of stuffing with mailing lists.