Hi – I’m sorry to hear you are experiencing difficulties.
This could be either a problem with your theme or possibly another plugin. Can you try deactivating all other plugins (except for ours) and reverting to a default, unmodified theme such as Twenty Twelve or Twenty Thirteen – and see if the comments work at that point?
If they do, please then reactivate everything else one-at-a-time, checking at each stage to see if comments have stopped working and hopefully we’ll be able to isolate whatever is conflicting.
Let us know how you get on 🙂