Standard Bank you can't just take money and then not respond to emails

On a few occasions I have seen small amounts going off from my Standard Bank account. I always, without fail, email them to enquire as to what these charges are for. And they NEVER respond. Like I said, the amounts are small but still, you can't just take money with no explanation. And these are random amounts just at random times over the weeks/months. And I am sure if they are taking these small amounts from all their customers on a regular basis, it amounts to a substantial amount in their coffers at the end of the month/year.

I want someone from Standard Bank to please have the courtesy to contact me and then to tell me what the amounts are for