Former financial ombudsman Walter Merricks first launched the legal claim in 2016.
He alleged that millions of shoppers in Britain were wrongly being charged fees on transactions made over a 15-year period between 1992 and 2008.
Consumers are still waiting to be able to claim compensation, set to be between £45 and £70 each, after delays due to legal challenges.
Mr Merricks shared this week that legal claims have been dropped and consumers will be able to start the process of receiving the money by the end of this year, The Sun reports.
At least £100 million will be distributed equally between people who claim, with consumers expected to get no less than £45. The exact amount will be revealed early next year.
“Most people who are now over 34 and who shopped in supermarkets between May 1992 and June 2008 will be eligible to claim, regardless of whether they ever had a Mastercard card,” he added.
The claims process is set to launch “in the coming months”, and those who think they may be entitled to money will have six months to register their claim.
Payments will be made at the six-month period ends which will fall in the first half of 2027.
People will be able to receive the payment into their bank account or through a gift voucher emailed to them.
The option to donate the money to one of a small number of national charities is also being explored.
Alex Neill, co-founder of Consumer Voice said: “This is great news for millions of hard-pressed consumers.
“Shoppers will soon be able to claim at least £45 in cash they’re owed.
“When the process opens, make sure you don’t miss out.”
