Personal Information Shared with Third Party

Good day,

I would like to know why my personal notifications and information is being shared with a third party.

An acquaintance of mine's cell number, received the below message detailing my personal affairs.

"Standard Bank: Hi Carel You qualify for a reduced debit order on your existing Personal Loan, based on your current outstanding balance. Reply 1 for more information. Ts&Cs apply. Queries ***"

This is unacceptable and I would like clarification and a resolution as soon as possible.

Why is a third party's personal cell number on my account details?

Why is my personal information shared with a third party?

Regards,

Carel