Mr Price Home extremely poor online service

On the 26th of August 2022 I did an online purchase with store payment within a few hours. A few hours subsequent to that I received an email advising some items were not available. I was advised via the helpline that I would receive a refund. After a few days of not receiving a refund voucher I called the helpline and then received a voucher lower than the refund amount. Every time I try to query this the ticket came back as 'resolved'. I tried the website contact form with the same result. Calling the helpline again (and finally going through) resulted in a 27 minute call with me being cut off while the consultant 'consulted' with managers. The store where I had made the payment cannot help as the manager said it was an online transaction and not at the store. I don't know what recourse I have left.