If the IRD is failing in one month, take it back to the LBS. They should replace it or refund it for you.

Most people find the new Shimano freewheels to be very reliable. Sheldon Brown raved about them. I did manage to bend the largest cog on one a few years ago riding it in winter snow and ice conditions. I'm not certain how it happened. But since I had pulled it off a dump find bike, I had no warranty options.

Your other option is to find a 7 speed Suntour on ebay. They can be pricey. I use Suntour freewheels almost exclusively, and have never had one fail. Usually mine have a 30, 32, or 34 large cog on them.

Best of luck.