Logitech X-540 speakers not working?

I had bought a Logitech X-540 5.1 speakers in Hong Kong last year. For some reason the front right, front left, the sub-woofer and the center speakers are not working. Only the rear right and rear left speakers are working. Logitech India service centers refused to replace it as the guarantee was valid only in Hong Kong it seems. Please tell me what to do?