Here is what I understand from the FAQ:
https://telegram.org/faq_spam
Q: What do I do now?
If this happened to you for the first time (and you are not an industrial scale spammer), most likely your account will be limited for a few days or so. Please wait and consider that people want a peaceful time using our messenger.
Repeated offences will result in longer periods of being blocked. If you keep writing unwanted messages to strangers, you may lose the ability to do so forever.
Q: I read all of the above, and Im certain that I didnt break any rules!
If you are sure that the limit was wrongfully applied to your account, please contact our @SpamBot.
Please forgive us for the inconvenience even the best systems, algorithms and well-trained people can make mistakes sometimes.
So I guess the best thing you can is contact @SpamBot and put as much detail as possible and explain what happen. Tell them that someone competitor (according to you) has sabotage your account and you didn't violate any rules. Goodluck!!!
You have to wait though, as they explain they aren't bots, might take days before you will get the final decision from them.