Milex airfyer not heating under warranty but we must pay

We bought an airfryer last year an my husband was convinced to buy the salesperson to buy this brand i knew this brand is not good quality this year airfryer stopped heating we took it back to makro centurion who confirmed it was still under warranty after 3 weeks at the milex warehouse we got an sms stating we should pay R300 i dint understand why as the airfryer is still under warranty ; this just confirmed tjst milex is not just a brand that provides very poor quality but also has distasteful customer service with no regard consumers