Bosch Service hiding behind T&C's

We bought a Bosch gas stove from Hirsch in Centurion on 2022-12-21. We now battle to light the oven burner and of the hob burners does not light up always. This is with a full new gas bottle. We submitted a call to Hirsch's along with the COC. Charlene Naidoo submitted it to Bosch Service. The stove has a 3 year guarantee. Now Bosch called us to say their terms and conditions have changed and we have to pay a R600 call out fee to do repairs. We were not at all notified of this so-called change in T&C's I will definitely not consider Bosch in the future.