Istore doesn’t care about customers

I bought a pre owned iPhone 14 Pro and recieved a 12 mini. I have been calling, emailing, WhatsApping, filled in the online form and still no reply. Just got promises of being called back. So unprofessional of Istore. You swear this is my fault. They took the money now nobody cares. I just feel defeated. Please can Istore take their 12 mini phone back and just give my cash back! How can they even send the wrong phone? This problem could have got sorted out but no one cares.