M15X won't charge?

This problem started around a year ago I think, basically when I plugged in my charger to my laptop it said 'Plugged in, not charging', and I had to twist and fiddle with the charger cable connection to the laptop before it would begin charging. After a while it began to take longer and longer to initiate charging whilst fiddling with it. Eventually it reached a stage where it would only begin charging after fiddling with it for 5+ minutes, and then it would only charge to around 50% before stopping. Nowadays no matter how much I fiddle with it, it still says plugged in not charging, and the battery level is 3% so I can only use my laptop plugged in. Something else that may or may not be related, upon loading sometimes the message saying 'This is not the recommended shipped Dell charger' even though it definitely is, but this message has been appearing long before the problems started. So yeah, all help would be appreciated, thanks in advance.