Non-Existing Service From Standard Bank Home Loans

We have a home loan with Standard Bank for the past 14 years already. We took an excess bond in 2009 for an additional R78k. We were efficiently assisted and approved. I never noticed but I found that on my bond statement, the interest was extremely high and the remaining payment period was also extremely long. I know that when we took the excess bond, we never increased the terms from 20 years to 30 years, but according to my statement and a consultant at Standard Bank Home loans, the repayment period is over 30 years. I have been battling for nearly 7 months for someone to sort this out. Every time I phone the Home Loans department, they say they can't find the agreement. Every consultant says that they will escalate the matter and someone will contact me within 24 hours. Till today I am waiting. I am tired of this poor service. All I want is clarity as to what my original agreement says. This is absolutely shocking service from such a reputable institution. I will never recommend Standard Bank to anyone. Customer service does not exist here anymore...