Is it True that The law requires that a buyers postage costs are returned

It is totally untrue that the law requires that a buyer's postage costs are returned.

Most states have this under their consumer protection law:

There's no right to cancel contracts or purchase agreements. Whether you can receive a refund is dependent on the retailer's return and refund policies.

California Code:

Civil Code Section 1723 of the California state requires a retailer to post their Refund Policy if the policy contains unique requirements. For example, requirements that wouldn't be expected by an average consumer.

Check this link for all other states: