Install went wrong and has now cost me my business and the MD just hides behind emails!

Four weeks ago I moved into a new premises and asked Safricom to come and install wireless broadband in the new office knowing that I would have to wait for Telkom I thought let me support my local company! BAD MOVE. On the day of installation I was out of office and UN-able to monitor the whole installation but thinking these guys are professionals. I already installed a network for the office to work and drilled whole for cabling and everything. Does this smart ****y not then go drill more holes in the wall right next to my R22k computer and let the dust flow through it which intern then blew up my power supply my motherboard and then knocking out my R300k printer as well on communications board. This guy got such a fright he packed his stuff and left. Didn't even bother to clean up after himself. After 4 weeks now of chasing some or anyone to try resolve this the director himself claims he knows it all and he refuses to pay out! AS HE IS A PROFESSOR AND KNOWS IT ALL... I WOULD NOT RECOMMEND THIS COMPANY TO ANYONE WHO IS WILLING TO LOOSE EVERYTHING. After my install they had full access to my network and it seems they them some how breached my computers and opened them all up to a can of worms / VIRUSES. R65k in damages, R200k in lost revenue and not to mention future revenue due to me loosing clients over this period!