If you have and you have real proofs, bring them and I'll probably repent.
In light of that hypothetical but far-fetched pathway, there is probably no need for you to repent there.
With WhatsApp the claim was that if someone snuck a backdoor into it there are enough people watching it to make sure that it would be found out soon.
My point is that even more people are sceptical to Telegram and even dislike it strongly so there should be even better chances of someone discovering if something was broken.
I'm honestly interested.
I only intend to defend Telegram against lies (most of the time the claim that "it is not encrypted"), not to cover up any actual problems so if you comment on it or write a post about it I will read it and probably will upvote it.