There is very little you can do whit them. Some of them are just not cut for this business.I would include them in weekly messages which you are sending out any way and live it on that. They may change their opinion whit time but you can't wait for that.
Focus your support to one who are active ,the one who log in every day and do their best, they will be happy to get some help and support from you.
Hope this will help!Good luck to you!
