I never received a notice of renewal for the magazine, but I discovered an unauthorized charge of $26 for the magazine (Kiplinger's Personal Finance, in this case) on my credit card account. I contacted my credit card company, which put me on the phone line with Synapse. The customer service representative was rude, accusatory, and unhelpful, but eventually agreed to only a partial refund. The justification for the only partial refund was apparently because I had already received one or two issues of the magazine since the "renewal". I explained that I had never authorized the renewal and had never received a notice from them, but they wouldn't budge. I did get their address, for what it's worth. Also, here's their phone number: 800-205-9198, although it's nearly impossible to get to a live person when you call (my credit card company found I way; I could only get their automated system on my own.).

The credit card company agreed to pay the difference between what Synapse refunded and what they charged me, but I recommend you avoid this company, unless you want to deal with heartburn a year later.