HMRC Black hole?

Just having a post January desk tidying exercise and checked the online submission of some CT returns. I discover I have receipts for 2 CT600s submitted electronically late December/early January which don't show as received on the HMRC portal.

Quick call to them comes back with the reply they must have been rejected, send them again. When i pointed out I want the original submission date attached, I was told they'll "look into it".

I only did this because I was having a tidy up, ordinarily I wouldn't chase something I beleived to have been submitted and for which I have an online receipt. nor have I had any correspondence from HMRC saying the returns have been rejected.

Let's hope they have their act together for the mandatory online filing.