I’ve just been told that we have a £40 shortfall every month after our payments are taken, I cant seem to get any clarification regarding this…

If you contact Bulb I am sure they will clarify (mon-fri)
Are you sending in your readings withing the 2 day time frame? If not they will use estimates.

@darckling this is normally when your consumption is higher than the monthly Direct Debit. It looks like your usage has decreased since we have been getting into the summer months so it may well be that your account gets back into a good place over the coming summer months.