Debit Order Adjusted Without My Consent – How Did the Bank Allow This?

I recently discovered that a security service provider adjusted their debit order on my business account without my explicit approval or signature, and the bank processed it without any verification. No new mandate. No confirmation. Just deducted, and I only picked it up weeks later while reconciling accounts. When I confronted the service provider, they admitted in writing that they never got my authorisation. That leaves me with one question: how does the bank allow this to happen? This is not about the amount. It is about principle and process. If a third party can adjust a debit order without my consent, then what is stopping this from happening again? I would like someone from the bank to contact me directly to explain how this was permitted and what protections are actually in place for account holders.