Vodacom incompetence

Vodacom's incompetence cost me R200 for change of bank details for debit order. I changed bank details on 30 June 2018 & another debit order was processed 2 days later on previous bank account with the extra R100. When I phoned & enquired about the 2nd R100 & told them that I had changed bank details on 30 June 2018 they said that it takes about 5 days for the new bank account details to be processed. How is this possible with the latest technology etc. When details are changed it should reflect immediately on Vodacoms system. Being charged R100 for the service is unacceptable & paying R200 is blatant theft since Vodacom is an extreme profitable company due to exploiting low income earners. Due to Vodacoms incompetence I feel I should be refunded.