Plum should auto-stash for you every 4-5 days. If no deposits have been arranged for more than 10 days, please get in touch with our team via 'chat to a human', or by emailing at firstname.lastname@example.org.
This could be for different reasons:
Plum hasn't been able to save for you because you have a low bank balance. We have designed Plum not to take you into unauthorised overdraft unless you specifically enable it in the app. Once your bank balance is a bit higher, Plum will start saving for you.
You do have an overdraft but you have not set up Overdraft deposits with Plum. As mentioned, Plum will try to avoid putting you in overdraft so it will stop saving if you are close to dipping into it. However, if you have authorized overdraft with your bank, you need to set it up so Plum can function in it. To do so, go to Brain > Overdraft deposits.
You have an overdraft facility set up but your balance is close to the amount you set up not to go below. For instance, you have an arranged overdraft of -£200 but you set up Plum to save up until -£150. If your balance is -£145, Plum will not save for you. If you want plum to save beyond that, you can edit your overdraft settings by going to Brain > Overdraft deposits.