Speedo cable slipping out of place and not working;

[Mystaya]

Car:AE86
Motor: 20V silvertop to JDM T50
Issue: Speedo cable slipping out

Hi guys, recently I changed from an ADM box to a JDM box, and when I went to put everything back together I noticed the speedo not working, I pulled the connectors apart from the box and line to discover the cable was sitting well back from where it should be.. I pulled the protective wrap off to try and get to the cable and pull it up to where it's supposed to sit, however the first connection where the cable slides into, something broken in there and it keeps slipping out(not holding properly) while I managed to have it working for all of 5 minutes after all this, it still managed to fall out again.

How would I go about trying to fix it untill I can get a new one.

[dove grey 64]

Doesn't sound like there is much you can do until you get a new one.
gps speedo apps or just watch your rev counter and gearing to work out your speed.