Contrast Trim Socks

I'm not the type of person to moan about something as trivial as a sock but I'm disgustingly disappointed at these socks. My original purchase was only a month ago. After 2 days (not continual) use I noticed fraying of the knit on the heel so I got a needle and pulled them through to stop them snagging. On the third day of use the heel actually detached from the main body of the sock. so I took it back after about 2 weeks. I thought it must of been bad luck so I got a straight exchange and same thing happened again. bitterly disappointed at the pathetic quality of these socks and I've lost faith in Marks and Spencers clothing due to this.