Double deduction on Pick and pay app

On 3rd August I made a purchase on die Pick and Pay app. The money was deducted twice and not refunded yet. I have checked my bank statement and saw that only one amount went off and the other amount is still waiting on Auth. I was informed byy bank that they require an authorized letter from Pick and Pay where they state that they have received the funds and this amount should be refunded to me. This massage I have conveid to Pick and Pay and have yet received any feedback.