Dissatisfied with quality of work and customer service from trades - what do I do?

TiredDonna

I've got an on-going problem with a plumbing company, both the quality of the work and poor communications from them. I paid their invoice promptly on being told the work had been done, but then the leak started again. 8 days ago their engineer came out, acknowledged the problem and said he wasn't happy with his colleague's work so he capped the pipe (it was out-of-hours) and I'm still waiting for the fix. Been in all day waiting in the 12 'til 5 slot, chased at 3 and chased again just now to have a very shoddy reply from the office and that the engineer would be here this evening.
I am so frustrated and angry and want to address this.
What should I do? And what can I expect?
I asked for their complaints procedure and was told I "could write to the director". I've emailed for a copy of their complaints procedure but am not holding my breath.