Standard Trust Limited's poor service

Standard Trust Limited is pathetic to deal with. They do not answer their telephones or emails addressed to them. They gave me a complaint reference number *** and promised to get back to me by 31 May 2022. Despite numerous follow-up emails sent by me ... I have still not received a response. I was on hold for 40 minutes today listening to the worst tune and finally hung up. I was number 17 in the queue and was told by a recording machine that the call would be answered in ten minutes. So much for that. I am at my Wits end. The estate is small and should've taken 18 months. It has now been almost 3 years and their is no resolution in sight