Sanlam disinvestment problems

I have a unit trust with Sanlam that is funded by debit order. Everything was fine until a couple of months ago. Recently, the debit order goes off as normal then a day or 2 later, the fund disinvests an amount and pays it into my bank account.

I have no idea why it does this. No one at Sanlam can tell me why it does this. Emails are ignored.