Sorted!
Your memo was wrong by the way, but I found the correct one here -
https://dashboard.internetcomputer.org/transaction/fef2f716a5a9afa187fad47d2c3e617ed8c4188e807cc6ee07d32a0fd85c9fe9
Then I ran this command and it refreshed the neuron -
dfx canister --network=mercury --no-wallet call governance claim_or_refresh_neuron_from_account ‘(record {controller=principal “t2u5w-xamy3-wzf2u-bgfxx-wiv4h-mezc7-v6pbe-oblz4-bzzub-44qvv-vae”; memo=8312538503409505771})’
The --no-wallet argument was introduced in DFX version 0.7.0 which I don’t think has been made generally available.
But you can still install it by running the following -
DFX_VERSION=0.7.0 sh -ci “$(curl -fsSL https://sdk.dfinity.org/install.sh)”
Or you may just be able to run the command without the --no-wallet arg but I’m not 100% sure on that one.