Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble.
On your 2 line (single) jack, it will have 4 wires coming in. The 2 on the inside are one "pair" (ring and tip), with the outside 2 being another pair. Typically the 2 inside would be line 1, the outside 2 are line 2. So just take the 2 outside and move them to the inside pair of the new jack, leaving the original alone. This will give you 2 separate single line jacks.
The line 1 should be red/green, and yellow/black will be L2.
Well your wiring is not standard, whomever are set it up has some wrong color pairs, but the top 2 on the picture are going to be the outside conductors (l2) and bottom 2 are the inside pair or line 1. So if you want to change those 2 around, then you're just flipping the top and bottom wires.