I just get a few fans per day
If you have enough credits in your account but only a few fans get taught per day
you should probably try to set the filters of the campaign down.
The weaker you set your filters, the more fans you get taught per day.
You should also check if you have other limits (eg max. Fans per day) or a total number of fans for the campaign activated.
Take also care of the campaign is not paused.