EE Home Broadband.
It took me a good three goes (2 months in total and a £40 data bill!) to get hold of EE's home broadband. The first time, there was a broken line. The second time, they attempted to connect to my upstairs neighbour instead, but third time was definitely lucky!
Router arrived in beautiful condition - very surprised to see how compact and cute it is. Engineer popped round and was super friendly. He went above and beyond to ensure my connection was fixed and stable.
At the registration stage and the following two attempts, I spoke to four very lovely people at their call centre. They were only too happy to help and rectified the situation very quickly. I was provided with a QuidCo reference to when we finally got up and running so my original purchase could track.
I'm still waiting for cashback but the estimated time is end of August. Here's hoping!
Edit: Cashback arrived mid-September :)