Mr Price - where is my money?

I purhased 3 items using the online facility. Order Confirmation #***. The parcel arrived in store with only 2 items. I was told that the 3rd item was out of stock and I would receive a voucher via email to the value of the missing item. This was the 23rd January 2021. To date I have note received anything even though I have tried to mail them directly and visit the store were I collected my parcel. This is really poor service!!! I was hoping for aseamless and easy transaction or return process like so many other online shopping sites BUT Mr Price has left me dissappointed and out of pocket. How do I get my money back?