Mac Robert Attorneys bullying tactics

I have a payment arrangement in place. Now these people threaten and harass me because they say I need to pay an exorbitant amount per month, which is not what had been agreed to for years in terms of a payment arrangement, and then they threaten and intimidate you with a summons and legal action because I insist that if the Arrangement needs to change they need to put it in writing and give me notice ? I don’t know how Standard Bank utilise them and approve their bullying tactics. Disgusting abysmal behaviour for a debt collector. Shame on your Standard Bank.