National Home Gardening Club Promised a refund in 4 weeks when I cancelled my subscription, haven't received it. Minnetonka MN

This club, initiated via an unsolicited mailing, is worthless. They promise free products, regular magazines, none of which were fulfilled, except a trowel which broke the first time I used it and pruning shears. I paid $24 for 2 years and requested a refund and cancellation after 1 year. An e/mail response said they cancelled the subscription, but after 6 weeks (promised in 4 weeks) there has been no communication nor a refund. I wish I had investigated further before being sucked into the promises.