“If a policyholder had paid $27,000 in premiums and did not have any claims,” wrote Julie Westermann, a spokeswoman for Genworth, in an email, then that customer “would have a maximum available benefit of $27,000.”

For Ms. Sparks — whose elderly parents, the Cooks, faced the near doubling of their life insurance bill — the insurance company’s strategy was clear: persuade her parents to simply walk away from the policy, despite a quarter-century of paying in.

“There’s no doubt in my mind that they were trying to get us to drop the policy,” Ms. Sparks said.

She said the insurer, Transamerica Life Insurance, sent the family charts showing the financial damage her parents would suffer if her mother lived a few more years. The charts showed that keeping the policy at the higher monthly payments “would have wiped them out for everything they had,” Ms. Sparks said.

In recent years, Transamerica has used a series of complex financial transactions to shift a large share of its obligations to policyholders into off-balance-sheet vehicles. That allowed it to send about $2 billion in “extraordinary dividends” to its corporate parent in the Netherlands, Aegon.

That left a hole in Transamerica’s finances, which policyholders like the Cooks are now being forced to fill, according to one of several federal lawsuits filed against the insurer seeking class-action status. Lawyers in those cases are seeking an injunction to block the rate increase.

Transamerica said it was “in full compliance with its contractual obligations, and intends to contest vigorously the recently filed litigation.”

After months of considering their options, the Cooks ultimately decided to drop their life policy, walking away from the $55,000 that they had spent on it over the last 25 years, Ms. Sparks said. They took the remaining cash in the account, which totaled $4,100.