Refund Department Extremely Poor Service

I am a regular customer at Builders and never had any issues with their products or delivery, in fact their service has always been great. However, on the 15th of July I made an online purchase and immediately the website said payment unsuccessful, I then checked my bank account and noticed that the funds had been deducted and I could not understand why the purchase was unsuccessful. I reached out to builders, they responded with a refund form and requested additional information eg. the proof of payment, bank confirmation etc. All the requested information was provided however it's been 3 weeks and still no refund, I have been emailing and calling and each time told the exact same thing "Our debtors department will get back to you". This has now become UNACCEPTABLE, I am a single mother, and this is my hard-earned money, I work extremely hard and now I have to BEG for my own money.

Can someone senior at builders please look into the matter with urgency as the money is needed. Thank you.