Student Loan Interest Rate Increase

I have a student loan with Standard Bank and I have been paying it back progressively with a fixed interest rate of 10.5% yet on my last statement I noticed the interest rate jumped to 15.5% without any warning. I ask how is this possible without any warning and how do they expect you to pay back if your interest jumps in such extraordinary ways???

When I noticed this I lodged a complaint/query with the inquiries desk (Friday 15/12/2017) and received an sms that the issue has been resolved (Friday 15/12/2017) and I will be contacted.

Today (Wednesday 20/12/2017) I had to phoned them to hear that the resolution was that i need to go into a branch to resolved the problem. Why has no one from Standard Bank contacted me with regards to this issues as well as not provided me with a contact number for the student loans department?

Every time I ask for a number for student loans they say they don't have a number and can only email them? How do they expect anything to get resolved with the sort of structures in place?

Will be closing all accounts with STD Bank and advising everyone to not deal with them as I have had endless issues with the banks lack of service in the past as well.