Cancellation not done and money went of bank account

On Air phoned me in August request if I would like to take out an Explorer I told them it is fine, they told me that the first payment will go off end of October. I received the Explorer but the people came out to install it and they told my husband that it will not work for a dual view. I phoned On Air to send the courier service to fetch the Explorer and cancel the Explorer. On Air and Hotspotter took money from my bank account, I phoned them and asked them to refund my money, they told me that they will exculate my request this is already neatly 20 days and no response. Now if I try to phone, number goes on voicemail. I want my money bank into my account and all debiet orders cancelled. Mrs JCC Venter