NON-PAYMENT AFTER WORK HAS BEEN DONE

I would like to get an assistance on exposing this company for a non payment after I've done a good work for them on the contract they had with RAND WATER on few sites, I tried to raise this matter with rand water but it seems like nobody take me serious , I'm still trying a away of exposing this on social media or any where , where Rand water will have to stand up on sub-contractors that are used by their contractors This company its owing me more than R100000.00 and they've been having stories day by day I can retrieve the emails of our communication