Swimming Pool disater!!!!

I contacted Robert Smit for a quote regarding my swimming pool. The quote was excepted and on completion of the job paid in full. Robert than issued me a FIVE year warranty certificate. A few days later the fibre glass stared to pull away from the sides and the pool was leaking. After an endless battle of almost 8 weeks in which I have tried in vain to get him to attend to the problems, nothing really has been done. It is the one hollow promise to another lie and now he just do not respond to any phone calls or messages. What can I do!!!