Sa Taxi’s “unpaid” installment & constant balance

My 58 year old mother bought a taxi in 2019 through Sa Taxi . Through out the years she has had the vehicle she has never not paid her installment. As means to even avoid that she asked that her monthly installment to be reduced. Her monthly installment now is R14000+ . She called in Jan this year to ask for her settlement balance & it was given to her. She called again this month , 12 months later, and they said her balance was R40 000 different from the balance they had given her 12 months back. On top of that they are now saying there were two installments that were not paid of which they have NEVER mentioned that before . Due to the stress that this company has inflicted on my mother her health has gotten very detrimental. Please help my mother urgently before she loses her life & all her hard earned money to this company. My mom’s contact details are ***.