I'd have taken the phone into a service centre as soon as the first line problem occurred. I wouldn't have wasted time on the phone. At that time, you were still under warranty, and so you wouldn't have had to pay anything. I'd have definitely taken it in for repair when the line got bigger, but instead, you continued to use the phone until the issue got worse, and eventually the screen failed altogether. By that time, the warranty had also run out! Why? Why wait so long? I don't get it. Like you say, it's a £1400 phone. If my new car engine develops a fault, I don't carry on driving it and waste time on the phone...it's straight into the garage.