[mothered]

So what is the move if the company and courier says it was delivered but no signature or photo etc was taken?

Under the circumstances, It has a very high chance of success.

Essentially, If you remain adamant and persevere with the claim (If need be, escalate It) a favorable outcome Is expected.

Whats the next step after that as they'll likely decline a refund from there

Say that a family member accepted the package In your absence, then return It for a legit refund, and reorder It on a different account and SE It using another method.