I'm assuming you're level 4 or higher.

The reason you cannot add any skill points is because these players have automatically been put on the negotiations list and people have bid on them.

You will need to log onto a PC (Negotiations aren't available on iOS yet), go to the squad section, click on your player, go to the offers tab, and decline the transfer offer.

You can also wait 24 hours for the offer to expire.

Other than that, you're stuck buddy!