Jd financial services poor client service

I had an account with Russells and I paid it up on the 21st of December 2020. After I settled their account they still deducted their monthly installment on the 28th. I realized that I had settled using the wrong reference so I sent an email telling them that and asking for a refund, which was on the 5th of January 2021. I was asked to email proof of payment and bank statements proving that I paid and that they deducted. Email was sent on the 13th. On the 25th of January 2021 they deducted the installment again and they still had not refunded the December 2020 installment. I have made several complaints to them and still no feedback. I can not wait 2months for a refund its ridiculous. I sent bank statements again last week and no one got back to me. The service that I have recipe is very poor.