Op has used his policy, he insured his bike for x for the year, has had a total loss and therefore there is no insurable asset left so the policy is cancelled. Just because it could have been paid monthly doesn’t change that. He has given them money for the years cover they have given him some back on the claim.
Some companies will allow you to run the policy on but normally it needs to be a similar risk. In ops case he wants tpo which is a different policy so needs to cancel existing and start again, losing his original premium.
Bad for us, good for the insurers, but such is life. File it along with every other reason they want more money off you for.