Birk's Landscaping Inc

My new walkway and front steps were installed the week of August 20 - 24, 2018 and looked great. Lezlie was good to work with and the crew worked hard and were very pleasant.
HOWEVER - On May 29, 2019 I was doing yard work and noticed the polymeric sand was cracked and shrinking away from some of the stones in one area - maybe a dozen stones involved; this is an invitation for weeds and ants to find a home! I immediately called the office, explained the problem to Jen and she said she would talk to the boss. I got a voice message the same day from her telling me the boss says the sand is not covered under the warranty but they could tell me the name and colour of the sand and I could fix it myself. I called back that day and told Jen that after paying that amount of money their response was unacceptable. The back of the Contract Proposal states under Section 4. Stonework, point a. Stonework is guaranteed for a period of 2 years and under point e. Use of polymeric sand included. Nowhere does it say the sand isn't included in the warranty. How would the stones stay in place without the sand; it's an integral part of the "stonework". What does the 2 year guarantee cover? She said she would check with the boss again and call me back. I didn't hear from anybody so I called again June 11, 2019 and Jen apologized for not calling back. I asked her to talk with the boss again or have Lezlie come over and have a look at the area in question. Later that day I had a voice message from a "Private Caller" and it was Lezlie telling me the sand is not included in the warranty but when she's in the neighbourhood she'll come and have a look; no indication of day or time and no way of calling her back to set an appointment.
While Birk's upfront service is good and they're quick to take your money, their follow up customer service is non-existent. I am extremely disappointed and will tell people considering hiring Birk's to steer clear.
UPDATE JUNE 14th: Lezlie came by yesterday and told me she had just found out about my concerns the previous day. She reiterated the fact that the sand is not covered under their warranty. She looked at the area involved and said the sand may have cracked because there is a very slight slope in the ground but she will arrange to have someone come out and take care of it. Rob came out this morning and explained what he was going to do. When I got home this afternoon I checked out the repair, it looks great and is now re-enforced by metal edging. I'm sure if I had talked with Lezlie initially this problem would have been dealt with promptly hence the change in my rating.