I love the originality of your ideas, the fetishization of the mundane. Junk mail and bank charges. LOL
For me they would only work if it was a female owned and run company as the opposite gender dynamic has to be involved.
I have always thought the best female financial exploiters would not necessarily hail from the BDSM backwaters but be high achieving women in society.
I secretly envy anyone who has encountered and been subsequently skinned alive by a 24 carat bitch of an estate agent or loan shark, banker or mortgage lender.
No leather or chains in sight, just a million dollar two piece, high heels, a little touch of cleavage and bang go your savings locked by her into high risk/low yield but providing her a stonking great bonus for finding another sucker. In effect she has just taken a huge bite out of your savings and then left the rest to rot.
Way to go !!!