refused with refund

i recently paid off my loan with capfin ,however they still debited and sent me a sms same saying they will refund me within 48 hours. i never received the money and when i follow up they say the money on their records shows that it was paid, then asked for my bank statements and sent to them. they can see from my bank statement that i never received my refund but they still not going me back my refund and they said they do not know whose bank account it was sent tol