Do these crawling insects have soft bodies or hard shells? If they have soft bodies, they may be susceptible to soapy sprays...not detergent, but liquid soaps.
I like to use ends of old bars of soap (I use castile soap and fragrance-free Neutrogena myself, and when I get down to slivers, I just put them into a jar, so they're available when I want a plant-friendly insecticide).
I break off a small piece of soap and dissolve it (stirring) in a cup or so of hot hot hot water. The HOT helps with the dissolving. Then I let it cool off, maybe putting a drop or two--really, that's all--of olive oil in the soap mix.
If you start with liquid soap already, try 1 tsp. per quart to begin with and maybe 1/4 tsp. oil in that same quart.
Put the mix into a spray bottle (or maybe just make it up in the spray bottle, since you won't have to dissolve anything) and spray the daylights out of those bugs.
This works on soft-bodied insects like aphids and ants, and many others as well. I can only vouch personally for the aphids and ants, though. (And if I find ants in my kitchen vs. in my garden, I just spray 'em with the cleaner Fantastik, and that does the job.)
The Neem probably isn't doing the job b/c, to my knowledge, it just doesn't soak into the soil; it clings to the leaves and stems of a plant.
Try the soap if they're soft-bodied. Spray it directly on the bugs, whether they're on the soil or on the plant.
Remember (not directed so much to you as to anyone who may just drop in and read this message): SOAP not detergent.