Watt bot is useless.
Best answer by stephenrand
1. You should always be roughly one month's payment in credit because you pay in advance for your energy.
2. It's not unusual to build up credit in the summer months, because despite the split summer/winter payments the summer payments may still be in excess of many people's usage if heating is a big proportion of it. It certainly happens to me.
3. Pure Planet review your account about every six months and suggest an adjustment if needed.
4. You can request a refund by going to Wattbot - make sure you put 'message the team' in the subject box and then explain the situation.
Hope that helps