Some Contacts Happen to find my New WhatsApp Number somehow

Hey thanks for the response...

It could have been like you mentioned but I happened to contact few of my friends and narrated my saga and asked them to have a watch continuously for few hours, turn by turn, meantime communicating with each other simultaneously between us, as to who is going to stay for the next few minutes to just peep in to their activities, (I passed on few numbers to them which I found suspicious). What we all noticed is - whenever I am offline, they are also idle and once am online, all of them come online together and after few seconds, only one will stay until am online...When I go offline, my friends, who would be watching this, say they also went offline after staying there for few more seconds, after me. Now this is repeating every time am online and offline...This happened with few of my numbers, until I got an idea, that they might have got my numbers through Telegram app (which I had installed and every time I changed my previous number to new, for whatsapp, I would change the number for Telegram as well) because in telegram there is an option of showing or hiding your number and that was open in my settings and if you change your number, the synced contacts could get those number as well...Now, after this, I asked one of my friends to get a new number, that too from the country of his stay and told him, once I install whatsapp in my mobile (in my country), just call me for the OTP he received so as to configure the whatsapp installation. Then I deleted all the system folders of all the social media apps like Facebook, telegram, whatspp, etc what ever I had installed into my mobile, Factory reset my phone twice, put Antivirus and then reinstalled new whatsapp using the new number but still the same activities could be seen from their side after a couple of hours...This is what my question...How? I hope you understood what I would like to say, though a bit lengthy..Thanks.

thanks for the reply, Please go through my actual concern and once more I request you or anyone to answer that and my basic question is not whatsapp, facebook, telegram or even signal...My concern is how they are getting to know my mobile number (last one is totally new and from one of my friends in a different country) and having a watch on me...please read out my previous concern and queries...