Welcome to the BUnnings Workshop community. It's magnificent to have you join us, and thank you for sharing your questions about your balcony chair.
I'm sorry to hear that the fabric on your chair has been damaged. This often happens when the chair has been left exposed to the elements for a long time. Eventually, the sun makes the material brittle and you get a tear-out. In order to repair the chair, you'll have to find out if it can be disassembled. Are there screws or clips holding the old fabric in place? Look carefully at how it has been put together. If you can see where the joining and holding parts are, the chair can be repaired.