Log onto your account through the runescape homepage, then go to account settings and click account status.
There you will see a list of your offences, click on the bot busting offence and then click appeal. Provide whatever information you have to prove you weren't botting.
If you were logged on a botting client, I have heard of them detecting them a few years ago and banning accs for being logged on a botting client. May be different now. If this is the case, I doubt they will remove the offence. Usually it is only a 2 day ban unless this is not your first botting offence.