Do you mean you left the bot "paused"?
Tutorial - Wallet and Premium Bots FAQ
If the bot uses breaks, you will still be charged for the break time period as the bot is still in use. If you manually pause the bot, you will still be charged for the break time period as the bot is still in use and connected to RuneMate's servers.
If the bot breaks, doesn't work or you are overcharged and you feel as though you deserve a refund, post in the relevant forum thread for the bot you are using, providing supporting evidence (eg: how the bug occurred and log files) and it is at the author's discretion whether they refund you.
You could try your luck with the last point above, but it is completely at the bot author's discretion as to whether they refund you.