It's highly likely that you will be charged for more than a month, as they love bogus unauthorized charges there. Why don't you try a pay-per-letter site, i. E.
https://j4l.com/402007
You know exactly what you're paying for and you can check it out to see if you like it for a much lower price than Columbiancupid membership. Another trick with CC, when you buy membership, lots of your contacts will disappear, they will not write you back. The reason is that CC uses bots to attract clients, they make you believe that you are very popular, in order to make you pay.