A popular website that helps people find the best charity to support has been taken over by a commercial firm which demands they provide their name and address and accept cold calling.

The Nationale Goed Doelen Test foundation, founded in 2010, has been bought by the Pepperminds marketing company in Haarlem. Pepperminds raises money for charity, mainly through street sellers, and takes up to one year’s donations in commission, the AD says on Tuesday.

Businessman Bart Hartman, who founded the website, confirmed the sale to the AD and said the contract ensures Pepperminds will not ‘abuse’ information about donors.

However, philanthropy professor Theo Schuyt told the paper there needs to be complete transparency. ‘You should be getting objective information about charities, not passing on your details which can be used for marketing purposes,’ he said.

Users of the site cannot access the charity recommendations unless they complete the information form and give the website permission to contact them about donations.

Pepperminds did not comment on the AD’s article.