Worst service in refunds

Bad experience. I settled my account with Capfin on 28 April. I received a SMS thanking me for my payment. When I paid the account, I entered their e mail address on my banking app. The POP would then automatically reach Capfin. On 3 May, Capfin deducted the monthly payment. I phoned them on 3 May and they promised a refund within 48 hours. Today (9 May), I phoned again in the morning. They said that their finance dept will phone me back. 2 hours later I phoned again. They said that their is no POP on the system and without that they cannot refund me. How can that be? My payment shows on their system!!!