Refusal to honour warranty

My tyre was slashed by a cracked drainage pipe on the pavement on Friday around 16:30. I’m a single female, so my neighbor tried to change the tyre and failed to remove the lock nut with the kit supp**** by the dealership. On Saturday morning I called Weiss VW Stamford Hill Rd Durban and explained the issue. The guys from the dealership came out and tried to remove the nut from around 9 to 12 but failed. They informed me to call VW SA this morning. I called them and explained the whole situation. They confirmed that the car is still under warranty and that they will make arrangements to send out their team to assist within 10 minutes. They then called back and informed me that they spoke to the dealership and because we tried to replace the tyre the warranty has fallen away. She used some unfami**** term that I’m guessing had to do with the locknut thread, but not sure. Firstly the dealership should have informed me that I should have not tried to replace the tyre and they should have not tried to for almost 3 hours to remove the locknut (there’s a possibility that they caused the damage) as it would effect the warranty. The blame was shifted to me although the dealership also tried to remove the locknut but failed so VW SA refused to assist me although the vehicle is under warranty. I’ve never experienced such hassles to remove a tyre and replace in all my 30 years of driving and then to be refused assistance for some technical issue.