Incapable to deliver promised service

On 2 September 2014 I signed a contract with Glass Vendor. Scope of work was as follow: Removal of existing skylight and upper wood structure, Supply & fit new bronze powder coated aluminium structure,Waterproofing onto existing wall (No allowance is made for painting walls), Fit 8.37 dark bronze safety laminated glass to tone in with existing structure,Allowance for 200mm overthrow with aluminium finish to the glass and Scaffolding is included in cost. A 75% deposit was expected. By February 2015 I was still waiting for the job to be done. Promise after promise was broken by Glass Vendor and at some stage I realised they were incapable of doing the job. Chris Pretorius arrived on my property during the last week of February 2015 with a promise the job will be finished by 28 February. Nothing happened! In the end on Thursday 5 March my skylights were installed by another company which they contracted out to do the job.Luckily the job was well done! There was no aluminium used and no 200mm overthrow with aluminium finish to the glass. Glass Vendor did not even bother to contact me but still invoiced the full amount. NEVER EVER USE THEM!