Vacuum Lock - Kinetico K5 RO System
It wasn't eht letting the water run out till the system stopped, it was the filter replacement procedure that mess it up. The filters have air in it and when you change filters you probably didn't prime the filters or remove the line to get the air out first. It may need a piston and a seal in the tank replaced to get it working again.
Is this what happened?
If the blue pin did not pop up, then maybe the correct filter (with gear wheel) was not in put in. What color was the label on that filter?