Producers and insurers selling Medicare supplement insurance policies are prohibited from which of the following?

Producers and insurers selling Medicare supplement insurance policies are prohibited from replacing existing policies with new ones unless certain conditions are met. This restriction is in place to protect consumers from unnecessary costs, ensuring they do not unintentionally lose benefits or incur additional fees by switching to a new policy without understanding the implications fully. Insurers must ensure that any new policy provides the same or better coverage than what the individual currently holds. This consumer protection regulation reinforces the importance of informed decision-making regarding Medicare supplement insurance, preventing agents from engaging in practices that could mislead clients or result in a loss of coverage benefits.

The other options, such as adjusting premiums or offering discounts, are not governed by the same prohibitive rules, allowing for flexibility in how policies are priced and marketed, as long as they adhere to overall regulations. Coverage termination can occur under specific circumstances, but it's typically defined by the policy terms rather than a prohibition against insurers.