Manager refuses to refund double dwruiopqerwbit

wrpowruile assured me the payment went to chiken licken De Deur yesterday to purchase food. the cashier told me payment declined, i checked my balance and informed her the payment was successful on my side. i there fore paid again and Zanele assured me the 1st payment will reverse. which it hasn't. spoke to Faiyaz the manager and he adviced i need to contact my bank to assist. how will my bank assist with a double purchase? i am not expected to drive back and forth to De Duer yet i live 30 km away. i have showed him my bank statement what more proof does he want?