I would write a letter of complaint, addressed to the IP by name and sent by recorded delivery. State the issue and mention that, if you do not have a satisfactory response within 28 days, you will escalate the complaint via the government gateway:
https://www.gov.uk/complain-about-insol ... actitioner
Be aware, however, that they might have the right, under the agreed terms, to extend this admin period, on prior written notice .... so the response could be that written notice.
It is not the norm for CF to be so tardy on completions, there may be a genuine hold up not of their doing. Hopefully they can explain more fully, rather than keep fobbing you off with excuses (which
is a CF habit!).
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014