Inconvenience and distress caused

So my mother recently purchased a gas geyser from this store however they did not provide the gas pump, they sent an installer on site only to find out that we need the gas pump which needs to be purchased separately, she then decided to return the product on the 28th of october ( original purchase date was the 17th of the same month ) She was told they will refund her

She was advised to return to the store with the card she used to purchase the gas geyser

She returned provided the details however they made a payment to the incorrect account to date she has still not been refunded and they are giving her the run around