Ending up with less money after a refund :)

Went to the store to return a computer monitor that was bought online. When processing the refund the cashier accidentally charged the refund amount instead of refunding the amount. They said they could not offer me a cash refund as they did not have enough cash. Now i am siting with R300 in my bank account for the weekend until the money reflects into my account which apparently will takes 3 business days. This is totally unacceptable and will not be supporting this company again.