No sure why yours have not been breeding. I live North of the US, and never provide heat for them or any extra humidity besides a dish of water crystals and they are prolific...I have way too many, but when I first started my colony it did take a while for me to see any babies...about 5 months.
They are live breeders, and so you will never see eggs. Are they in a dark spot? Apparently they like to be in the dark and pretty much left alone. Heating can help to jump start the breeding process, so a heating pad may help to keep them happy (or in the mood..lol). I have also heard that they tend to breed more when offered oranges. Not sure if this is true, but that is also something I did at the very beginning of my colony stages.