Failure to honour guarantee

In 2011 Cape Liquid Waterproofing waterproofed the terrace at the front of our house, which is above the garage. The job cost R30,000 and came with a ten-year guarantee. In winter 2020, during heavy rains, there was a bad leak in our garage. On 21/07/2020 I emailed Adriaan Visagie, the technical manager, who replied that Tania would let me know when a team would be in Cape Town. She was CCed. I followed up with her on 26/08, after not hearing anything. She did not reply. I emailed both Adriaan and Tania on 01/10, asking for an update. Adriaan gave me a vague answer about the weather and said someone would be in touch about arrangements. On 07/01/2021, after I had still not heard anything, I emailed again. Adriaan replied that they would be reopening on 18/01. On 23/03, after still not hearing anything, I emailed yet again. This time he did not bother to reply. I have been trying for over eight months to get them to fix the leak. What is the point of giving a ten-year guarantee if you refuse to honour it?