My opinion is that it's hard to think of a reason any parent would be denied supervised visits and phone calls. There are plenty of safe options: visitation center overseen by social workers, a therapeutic setting with a counselor, an outing in the community with a trusted friend or the foster parent(s), monitored phone calls and video chats.
The Wells may not be doing what they need to do to get the boys back, but I haven't read that that parental rights have been terminated. In my state, TPR is a huge deal; unless the parents consent, it involves witness testimony at a hearing before a judge. To implement a sort of de facto termination by not facilitating communication and visits - well, it happens, but it's not right IMO. I have no way of knowing if the Wells are telling the truth, but my experience has been that case workers and attorneys can definitely go radio-silent for long periods of time, regardless of what's best for a child or a family.