Cannot get instructions right!!!!!!!!!1

I pay for my mothers medical aid and changed my banking details from Nedbank to FNB. I closed the Nedbank account and made that known to the agent i was talking to on the phone. I was then told to write a letter to the scheme to alow them to change the account details. Today I wanted to submit a claim from a doctors visit and when I check my moms statement I see my old Nedbank details still loaded for refunds. I am now told to write another letter to change that.... How PATHETIC because why then did I ask to change my details before. The Nedbank account is CLOSED!!! how many letters should i write when I call I am told my mom needs to call and when she calls, I need to write letters.... such a waste of time.