Debit Order for Costs?

[MehmoodHaffejee]

OST had a message for update of details on log on; apparently this will be required every 90 days. My question is why does OST need to debit your transactional current) account for fees/charges when no transaction can be executed if funds are not sufficient. Is this for those traders/investors who do not have sufficient funds to pay monthly fees? This is a little confusing...

[SimonPB]

monthly fee is there not enough csh in account

[MehmoodHaffejee]

Its a standard update details request, but its got me worried as to why will OST need to debit my current (cheque) account for any costs???