I know lots of people who wouldn't touch them, but I've recently had to contact TalkTalk. They provide my landline and broadband.
Engineer at green box across road last Monday afternoon. Landline rang Monday evening and I thought it was a nuisance call, but could hear dialling in background. After that, couldn't get dialling tone. Finally reported it on Wednesday via their website; they diverted landline to mobile. Another engineer at green box on Wednesday afternoon, advised test would take 24-48 hours. Finally resolved lunchtime Friday.
It took a while, but everything fine now. All the staff I dealt with, including Friday's Openreach engineer, were fine, but I'm still wondering why it took three of them to put it right!