Poor Service

I am very disappointed with the service that I have received so far from apple. I recently purchased an iphone 12 pro on the 6th of January which i paid cash using my cheque card.A few days later I decided that i wanted to buy the iphone 12 pro max instead as i wanted the bigger phone. I send multiple emails to *** with no response whatsoever. I called the call centre who advised me that they cant assist and that i should speak to the online chat service sonsultants. I proceeded to do so and spoke to a gentlemen called Tshepo. This gentlemen advised me that he can refund me the R22499.00 because I needed to cancel my existing order first. He then informed me that he will refund me in the form of a voucher. I received two emails from istore online stating that i have a gift card of R10 499.00 and R12 000.00. I do find this strange though. Why was this broken down into two payments of R12 000.00 and R10 499.00 .Could the R22 499.00 not be loaded onto one voucher? My frustration is that when i try and use the vouchers then it gives me a zero balance ..I need this to be resolved urgently, if not then I will visit an istore and demand my money back .I'm new to apple and i have to say that the experience that Ive had so far has been very poor.