customer service & aftercare service are appalling

The customer service and aftercare service are appalling.

Firstly, it took the surveyor 3 visits to finally be able to complete his measurements (each time we had to wait in for most of the day).

My doors and windows were finely fitted on 4th December, but they brought the wrong door numbers with them. I was told they would come back to fit the correct ones.
It has taken me to contact them (after a week) and then to be given the earliest date of 10th January 2020 for them to come out and complete this work.
I find this a totally unacceptable time period to carry out this outstanding work caused by an error on their behalf.

I also had several other issues that had not been resolved.

I have made phone calls and sent emails, but both were in vain...I have either been on hold for on average over 10 minutes each time or my emails do not even get a response.

On a positive, the products appear good and the install team we had were very efficient.

However, based upon the extremely poor customer care I will not be using this company again.