CUSTOMER SERVICE AND QUALITY FAIL

I recently contracted this company to install aluminum door and window at my house and I must sadly say that I am less than impressed. Firstly I was advised that the "Sales Consultant" will be managing the process from end to end. I had to pay 95% of the total quote upfront before they will ever come to your premises. I find this quite unacceptable that companies insist on paying upfront before any work is done - this leaves the customer with little to NO recourse if the installation was not done right, substandard or of bad quality. I must admit that any future company that I ask, I will not pay anything upfront until the work has been completed, and satisfactory. As I work during the day, they send their "installers" to do the work. They are not briefed properly on what the actual and correct layout should be upfront - which is a concern in itself. It seems that the onus falls on you as the customer to ensure that they install in the correct place, have to supervise them and inspect everything. I am a working professional, so sadly I am not able to "supervise" - that is why i pay a professional company to do the work. The installation was done on a Thursday. Halfway through the installation and between work meetings, I went outside to see the progress and noticed that the door and the window was placed incorrectly (swopped to the incorrect side). I mentioned that to the installer and he almost fainted. I had to rush back to a meeting and said to him I will have to "see" if this configuration will work. That evening when I went to "lock" the sliding door, the lock just fell out. I immediately reported same to the Sales Consultant. The following day I checked the quality of the finishing and noticed that the sealing rubbers were not properly placed. I advised the Sales Consultant of this on the Sunday via Whatsapp. The following week when I ask him when will they sort the issues out - I get advised that I "only had" 48 hours to report of any issues (which apparently counts weekends in as well) and that I signed off the jobcard. They gave me only 2 options: (1) accept the incorrect configuration as is and they will send someone to check the rubbers and lock (2) pay additional R2000+ (including the 5% left from the original quote) upfront and they will come through to make the changes. Now I have an issue with that. Firstly, I am the customer - and they did a shoddy installation of which I am not happy with. I reported it to them and then I get dictated about what they are prepared to resolve. Then the Sales Consultant tells me that IF i reported it within the 48hrs, they would have immediately (note "immediately") sent out the installer to fix it. Its now 7 days later and I am still awaiting the "immediately" to happen. I then agree with them that they can come tomorrow (Friday) to come and fix the mess - stating that I will not pay anything until it has been resolved. When I follow up with them this afternoon, I am told that "sorry you did not confirm the 2 options, and we are already booked for Friday. Needless to say, this company is not interested in customer service. They are not interested in fixing their substandard and incorrect installation - and they dictate when/how they will be available. What has happened to customer service, quality of workmanship? In the end I guess I will just have to fork out the R5000 to pay them more because in this current state I am left with a substandard product, a door that does not lock (security risk for me) and a configuration that I did not want. Note - they sent someone out to measure the area where I specified the configuration. This is a lesson learnt - and I hope others can learn from this - DONT pay upfront, because you will be the only one sitting with the problems afterwards.