Septic tank ****

The short story - we were quoted a septic tank installation and connection to existing french drain. We received a water tank and a PVC pipe not connected to anything. The tank overflowing after a week's use. Detailed story - Schalla (Schalk) Spies from Pro Garden Route Landscaping presented himself as a qualified plumber with experience in septic tank installations and maintenance. He quoted on replacing our septic tank with a 2500L septic tank, check the french drain and the connection of the tank to the french drain. He provided the specs and product code of the Rototank septic tank and a detailed explanation of what he will be doing before we accepted the quote. After removing the old tank that collapsed he installed the new tank and filled the hole with what he said a mix of cement and soil about a third way up of the space. We were sent pictures of the installation throughout the project (as this is a holiday home.) and we made the payments as an when he requested and the pictures lined up with what he said. While busy wrapping up the cover of the hole he sent a video with voice showing that they are done and asked urgently for the final payment which we made (immediate payment). I arrived at the property the week after to find the sheets that he said would be bolted to lintels, blown away. He met two days later, apologising that he did not inspect and that he went with his worker's word that it was done - quite strange as I received a video with his voice right at the end stipulating the sheets are fixed to lintels. He discussed a different plan to cover the hole but also stated that most people just cover the tank with soil and that the septic tanks are much thicker than water tanks - they can be underground. We visited Rototank's website to double check and discovered that the tank he installed is a WATER tank and not the much more expensive septic tank. Rototank confirmed this and stated that a water tank can not be placed underground. During his visit Schalla also briefly showed me the "extension of the french drain" - a 2m long white PVC pipe going into the slope more or less in line with the tank and the open end towards the street. I questioned this and he said that it filers into the rocks and soil and then quickly changed the topic. After discovering the tank ****, I climbed down to the pipe and found that it was just covered with soil at the top - not connected to anything. The tank was not connected to anything at all, and already overflowing after just a weeks' use. I confronted him. He stuck to this is how he always does it and that this is the first time in 8 years of business that he encountered someone that is unhappy. He was willing to make the changes if we could say exactly what we wanted. I showed him his whats app confirmations of the septic tank specs and explained to him that I don't feel comfortable allowing him to fix the installation after the tank and pipe ****. We struggled to get to a point where he was willing to part refund us and then struggled to agree on an amount of 2 thirds of the total. He then informed us that he will make R5000 payment now and the rest in two weeks' time when his other big project pays. Needless to say we did not receive the second payment. When I enquired he rep**** that he cannot pay such a huge amount in one payment he will make R5000 down payments. He then paid R2500 and another two weeks later rep**** that he is willing to make monthly payments of between R3500 and R5000 if his financial situation allows. I don't think we will receive the full amount agreed on.