Un-authotised account access

I have been a customer of Absa Bank since 1976, formerly known as Volkskas Bank. I have never encountered any issues until recent months when unusual occurrences arose. Without my authorization, MTN, a service provider, accessed my bank account and initiated a debit order exceeding 3K, alongside a smaller amount that is less conspicuous. I have no prior association with MTN, prompting concerns about how they obtained my account details and executed the debit order.

I am uncertain whether this breach resulted from an internal compromise or vulnerabilities within Absa's systems. I promptly reported the incident to Absa's *****Line; however, assistance is only available on weekdays. I believe it is crucial for Absa to investigate this matter thoroughly.