Quick flow plumbing and heating ltd

Did a competent job fitting the mixer tap but not with the blocked sink. He made a hole in the drainage pipe and poured in Zep liquid heat drain unblocker liquid. This seemed to fix the problem but a week later the sink was almost completely blocked again. I got another plumber in who did the job properly using a Ridgid K-45 AF-5 Autofeed Drain Cleaning Machine. He also noticed that the pipe under the cupboard was too flat and changed it to improve the flow. Paul told me that he wasn't a drainage specialist and that if the problem returned I would need to get a drainage specialist with rods. The second plumber who actually fixed the problem did not consider himself to be a drainage specialist and said that the job was something any competent plumber should be able to do with the right equipment. He was highly critical of Paul's work and suggested that I ask for a refund. Paul refused to give me a refund.