Pathetic after sales service

All was good in the beginning until payment had been made. Paul the owners attitude then changed. About 6 months after the pool was installed the rock paving started cracking badly. Paul avoided calls but eventually answered when called from another number. He came to check and said he would have them repaired, but never showed. He gave a 3 year warranty but is nowhere to be found. About a year and some months later the fiber glass is peeling and pitting as well as the cracks have gotten bigger. I have tried calling Paul numerous times, sent emails and Whatsapp messages but he doesn't respond. This type of service is pathetic. My next step is to get a lawyer involved and sue for legal costs as well as costs for damages on the pool.