Sir Keir Starmer faced outrage after claiming pensioners would be “better off” under Labour.
The Chancellor insisted protecting the elderly was a priority, despite scrapping the winter heating grant for 10 million people.
He said the triple lock on state pensions, which will be paid out next spring, will mean some elderly people will receive an extra £400.
But Silver Voice said the comments were an “insult” to pensioners and “unbelievable”.
Director of the National Pension Service Denise Reid added: “The triple lock is intended to offset all rising household costs, not just energy, but the prices of food and other essentials are still rising.
“The majority of older people are still on the old State Pension (for those who left before April 2016) which has a maximum of £169.50 a week.
“Next April this will rise by £7 a week to £176.45.”
“Wealthy politicians would not bat an eye at spending that kind of money on dining out or Taylor’s concerts, as Swift would.”
The Express campaign to save on payments is supported by MPs from all political walks of life.
A petition calling on the Government to protect household pensioners will be delivered to 10 Downing Street today (Monday).
Mr Reid added: “I will be joining the Express tomorrow to deliver a major petition to 10 Downing Street calling for a budget to protect older people. Nearly 150,000 people have signed the petition so far.
“If Sir Keir is still there I would be happy to have a chat on the doorstep to get him back on the right track.”
The Chancellor of the Exchequer Rachel Reeves has been accused of delaying an increase to the Winter Heating Grant. She will launch an “attack on pensioners” with the £300.
Some long-time Labour voters have said they will never vote Labour again after this “cruel” policy.
The Government will scrap the General Winter Heating Allowance of £200 for pensioners under 80 and £300 for those over 80 in a bid to save £1.5bn.
Only those in receipt of pensions etc. will be eligible.
Mr Reeves announced the decision just three weeks after taking office in a bid to plug a £22bn spending hole.
But critics point out that half the money went towards huge public sector wage increases, paid without any trade-off with changing working practices.
Analysis by the opposition Labour Party found that limiting winter heating subsidies could lead to 3,850 deaths.
Research by Age UK suggests that almost all pensioners who are poor would lose their winter heating allowance.
The charity warned that around eight in 10 older people earning at or above the poverty line would see their subsidies cut this year.
She fears there could be a “catastrophe” if the weather changes unless there is a U-turn at home.
Nearly 23 percent of those who lost support were living in poverty or just above the poverty line, and 800,000 of them were over 80 years old.
It affects around 1.1 million pensioners with disabilities and a roughly equal number of older people living alone and struggling to make ends meet.
The decision also caused divisions in the Labour committee, with MPs and party members expressing concern about the impact.
Around 50 MPs abstained from the vote to introduce the reforms, the biggest rebellion yet for the new government.
Asked by the Express whether pensioners could be reassured that they had already borne the cost and would not be made worse off after the Budget, Sir Keir said: “We are keeping the economy stabilised. “
“This will allow us to maintain the triple lock. Keeping the triple lock in place means pensions will rise by more than £400 next year.
“That’s on top of the £900 state pension increase this year.
“That’s the pensions situation but I’m hopeful that under a Labour government pensions will be protected and it will get better.”