I have a similar situation regarding insurance, although car insurance and with a different marketplace. Avios cancelled with a generic statement, which I responded to and challenged, receiving a different reason six weeks later. This was also challenged and no response recieved for four weeks.

And since the move to 2FA, transactions just don't track anymore. I have 1 from 4 which tracked and three which didn't. Two of these were reported via missing avios twelve days ago (no reply) and one will be reported tomorrow when the five days are up.

It's incredibly frustrating. The car insurance like the OP was not taken for the avios award, but this was an added bonus. It is worth pursuing as it is 3,000 whereas the other transactions are too small to do anything beyond report and hope they award the avios. Any big spend will be taken elsewhere until the portal becomes more reliable, however.