Vodacom repair center can not repair!

<p> Good day,</p> <p>I have a phone on contract from Vodacom. Recently it started rebooting itself a few times a day. I took it to the Vodacom, and they upgraded the software. That did not solve the problem. When I took it back, they replaced the motherbord. That also did not solve it. The next time, they upgraded the software again. Still no luck. I found out that the problem I have, is common with the specific phone. Now...does the law not state that if there is an inherent fault with the product, it must be replaced? How many times should I take this phone back to Vodacom? I use the phone for my business, and can not afford to loose calls because the phone does not work! Either repair or replace!</p>