Discovery Health - No successful help from them!

I called Discovery Health to change my debit order date since my pay date with my employer has changed. Only for them to tell me that if they changed the debit date from the 25th to the 10th they will double debit me. Despite them confirming that they have received my installment for this month, they can't ensure they won't double debit me.

When I asked to change the date to the 1st of each month, they said they could do it and it shouldn't double debit me. HOWEVER, this change will only be effective from April!! Which means I will be charged by my bank again for penalties, due to no funds in my account. How is this accommodating a loyal customer who has been with them for 7 years? So I must just lose money again this coming month and be happy with it? This sounds impossible! This is disgusting! The lady who helped was honestly wonderful, but Discovery useless. Truly appalled by the lack of care and help from Discovery! I am still waiting for someone to get back to me.