Vodacom in bed with Standard Bank

I have been a longstanding client of Vodacom mobile telephone services until I realized that they were victimising me. There have been many problems with their billing system. Payment dates were changed arbitrarily without informing me beforehand. In addition, I must be the only Vodacom client whose account was paid 1 month in advance. As an abandoned wife, dependent on a widow's pension, Vodacom's tampering with agreed upon, contractually bound, payment dates, have led to the accrual of debt on my cellphone account. I have no intention of paying such debt. Standard Bank works hand in hand with cellphone network operators. THEY are BUSINEES PARTNERS while I am only a CASH-STRAPPED CLIENT.