how Mr. Chandler could refer to premiums paid as "all that wasted money"?

Anyone who buys insurance, pays a premium. That premium is in exchange for the Insurance Company's promise to provide insurance coverage for a specific time frame referred to as the policy term.

When the term ends, you pay a "renewal" premium for a new policy term.

Not much different from buying a pair of trousers at Belks. When they wear out, you buy a new pair.

By his own admission, they paid a claim on his behalf. They did what the policy called for.

Now they have decided they do not want to provide coverage in coastal areas. That's a business decision. No more; no less.

He paid his money; he got what he paid for.