PLANET SPARK - Company is not cancelling the services as agreed during the sales

We had purchased online classes for my son from Planet Spark for a Public speaking course and during the sale, the sale person promised that there would be ** day review period and if our son is not able to cope or if we do not like the services then no question will be asked and the amount will be refunded. We attend few classes and then noticed that online classed wont be suitable for our son and then informed the same to Tuor and also sent a cancellation mail request to Planet Spark over a mail and raised a issue request on there online platform but they are not ready to cancel and do the refund. First few days they responded over the mail and informed us they could not cancel and the course can be halted for few months and there is no policy of refund. When replied the statement which was agreed during the sale that "No question asked during the review of ** days" they stopped responding to mail and no one is contacting me.