Tell us everything that has led up to this point. What soil they are in, how you water, how often, be as detailed as you can about the environment of the plant
Hey A , do those plastic cups have drain holes in them ?
Get them out of there asap and into a proper 5 inch container, 5 inch , not t gal....
It looks like you have one cup , with drain ? Into another cup , maybe without drain ? = instant death
Your top leaves and tips look good , so maybe you are drowning the plant
Send a pic of the bottom of container....
I see a black loop , i guess you put into second container to bend and loop plant to slow down stretch ,
Next time , when a seedling stretches out of control , trsnsplant it deeper into a cup or pot instead of bending it...
Might have a better outcome....