Most, if not all of them, are scams for taking money off small business. The adverts will appear in calendars, wallplanners and such, which may only have a small print run or may even not be printed at all. If you say yes, then your details are passed to other such companies who will call you as well. Some who claim to be charities only give a small sum to the charity like £1 out of the three hundred you pay them as the rest will go on expenses. Stay well clear of them all.
I'll just add, don't give any of them your bank details.