Complaint on Coastal Glass & Aluminium Gansbaai

Ernest of Coastal Glass Aluminium Gansbaai gave us a quote to put one way window film on some of our windows. This was done 6 months ago, we told him straight away that we were not happy with the job done as their were bubbles in all the windows, after numerous phones calls of him a lot of times ignoring my calls, he sent his daughter 5 months later to come and look at the windows and she agreed that they all needed to be replaced and promised it would be done. A month later still no replacement, when I called their office to ask when it will be done I then later got an email with an excuse that her grandmother is ill and this is not the 1st excuse, the 1st one was the daughter has fibromyalgia and was too sick to come through, and if I wanted they would rather refund us our money which totalled R4100.00. I must state that in good faith we paid them in full as it is our home in Pearly Beach and we reside in Cape Town, and we trusted that they did a brilliant job, what a lesson to learn. Last week Friday, 14/12/2018 I called the office and spoke to Ester advising that I had received no refund. Ester said that Ernest was in Cape Town for the day and that the office would be open on the 17/12/2018 as they are working and payment would be made. Today 20/12/2018 still no money in my bank account and I tried to call the office of Coastal Glass yesterday and today, also tried Ernest on his cellphone ********** yesterday and today but no answer, I have also sent him a wattsapp and no reply after 6/7 months I am now at the end and would like to know what I can do from here to get my money back as Promised by Coastal Glass and Aluminium Gansbaai.