Why whatsapp with a specific contact fails to receive messages? I am not able to receive messages from a specific contact using whatsapp, but I am able to send to the that same contact.

All other contacts appear to be receiving and no issues with the send process.

Ps: I haven't blocked the contact where the issue is being reflected.

If relevant, I'm using Android 4.0 (ICS)
I realized I had a very symilar problem with a contact today.
Creating a group with only the problematic contact was a successful workaround, the final solution was deleting the original chat that stopped working and creating a new one.