Sadly, no, there really isn't any way to prove that. You can try submitting a ticket to Player Support, but they do not overturn any punishments issued by the Instant Feedback System. Additionally, per the Terms of Use, all players are responsible for any actions that occur on their account, even if it is something that occurred during a suspected compromise.
Was it during the bot matches played on your account? Other than those, I don't really see any matches that stand out as being unusual.
I wish I had more encouraging news for you, but all I can suggest is to try and make your next account more secure so that this doesn't happen again.