Super stressed at the moment.

A different situation here. I made a FLR under Tier 1 General. It was returned as I had ticked the wrong fee box despite the UKBA helpline advising that this was what I should be ticking.
Now my FLR has expired. The original FLR was submitted before expiry. I have resubmitted under ILR as I now meet the criteria with the Life in the UK test now passed. I have written a covering letter explaining the sitution.
What else can I do? I have no record that they gave me this advise. I don't know why they didn't contact me and say "look you selected the wrong fee and need to pay £1000 not £500".
Any advice pleaseeeee!