Partial refund for out of stock items by Grabitall

On 29th Nov 2020 I placed an order for 2xPatio Mist(R278) and a Donation (R5) which amounted to R305.40 including a discount(R56.60) and delivery(R79.00), Order No: #116394. On 11th Dec 2020 I got a mail from Grabitall that the items are out of stock from supplier, yet Grabitall still had an ad online for these items advertised on that very same day. I requested to be refunded my money back. On 21st Dec 2020, I received a proof of refund payment valued R135.20 which is not what I paid to Grabitall. 22nd Dec 2020 I responded asking why am I not being fully refunded and requesting to be fully refunded and Grabitall did not respond. 06th Jan 2021 I enquired again and to date Grabitall is ignoring my communications.