Online shopping refund

I made an online purchase (p***) on the 03/08/2020 using my tfg account, few days later I only received one item out of the two that I bought. I called them on the 24/08/2020in connection with the other item that was not included they said they didn't have a stock of that item and that they were going to do the crediting of my account within 5 days. I called again on the 11/09/2020 they said that it wasn't done, they were going to escalate this matter and that it was going to take 48 hours to do the crediting. I called today because they didn't not credit my account I was told that it was escalate but the is no feedback as yet and that the turnaround time is 1-10 days this really disappointing if you take into account that I've reported this month almost a month ago to make things worse is that no one from their side communicates with me about what is happening