MV Solar - *******ly withholding my COC due to their incorrect quotation

In Sept 2023 I, in good faith, accepted their quotation and they installed my solar. Before issuing their quotation, they never did an on-site inspection and, as they are based in Vereeniging, they used Google Maps to estimate materials needed. All the other service providers that came to give me a quotation, all visited and measured the premises. I advised MV Solar that I had two DB boards, one in the garage and one in the house. On the day of installation, the owner (who admitted this) had forgotten to tell his staff about the two DB boards, so they ran out of material and proceeded to hang the wiring across the walkway from the house to the garage. I complained (even my electrician confirmed this was incorrect), and they came to repair it. Then he issued a final invoice where the cost had increased by R5000! I refused to pay it, and since then he has withheld my COC certificate ,which he charged me for, and the courier fee to get it to me (his original quotation for that courier fee was R3000! from Vereeniging to Fourways!!). Legally, he cannot withhold my certificate. A few weeks after the installation, my electrician came and advised me of several items they had not done, which is why my electricity bill had not decreased. My electrician also advised me that the installation should have been tested and inspected by a certified electrician to sign off on the COC. This was never done! They came to repair the hanging piping and proceeded to leave a huge block of plaster off the wall, and didn't put the paving bricks back correctly. When I raised it with the owner and sent him photos, he agreed that the work was not acceptable and that they would come back and fix it. He has now stated that he has been over accommodating with my complaints........wow, when I am the client and their workmanship was shoddy (which he even agreed to and I have it on WhatsApp). One Solar panel started to dip last year, and I told him. He sent someone to fix it who advised me that the incorrect brackets were used on installation, as they weren't given the correct ones on that day!!! There is an earth leakage problem which was raised with the owner a month after the installation, and to date, he hasn't responded to that email nor to any of my other emails requesting my COC certificate. This week, there was a problem with my solar, and I contacted SunSync to find out what the warranty is on my Invertor and they advised me it hasn't been registered! This is MV Solar's responsibility, and it has to be registered with a copy of the COC certificate, which clearly hasn't been issued, even though I have paid for it. This week, my electrician has been and advised that there are several issues with the solar installation, like earthing, cable protection trunking, separation of cables and the list goes on. He will do a full report, attaching photos, and the cost to fix it, and we are now heading to the attorneys. Be wary of this company, especially as legally they cannot withhold your COC certificate, and he has been advised of such, but has continued to choose to withhold it as he wants me to pay the amount outstanding, which was his incorrect quotation. His reasoning states that in their email, it states they reserve the right to re-quote should they get to the premises and additional work is required. Please note re-quote was not added to your final invoice without discussing it with you, and should have been totally avoided if they did what every other business does and visited your premises prior to quoting and taking correct measurements. I accepted his quotation and I am not responsible for any additional costs due to him forgetting I had two DB boards!!!