Worse customer service-Refund related

I tried to pay for an order on Zando but the payment could go through, eventually when u made instantEft payment it went through but I still go an email saying I didn't pay for the order but the amount went out of my account. I queried this with the agent and she said I must send a screenshot of payflex, I didn't use payflex, I used instant payment, I sent my statement and still the got the same standard request from the agent, they can't allocate my money to the order because their system doesn't allow them but they also can't refund me because of the payflex screenshot I must send.. Which I didn't use... I used InstantEft... Sent you my bank statement, may I please have my refund... Honesty am frustrated by lack of understanding... I don't know how Zando systems work... I sent you proof that money went out of my account yet the Zando system says otherwise... This is not my problem. May I please have my refund immediately because the back a d forth is just ridiculous.