I can safely say I was the first customer in the AT&T at 82 Wall Street in New York to ask for the enhanced SIM card for the Isis mobile wallet.

After a little more than a year, Isis announced its public availability nationwide on Nov. 14.

I wasn't thrilled that the joint venture between AT&T, Verizon and T-Mobile decided to launch its mobile wallet only a week after temperatures in New York dropped below 30 degrees. But I bundled up and ventured out, excited about finally getting to use the Near Field Communication-enabled open-loop mobile wallet.

Since I don't have a card from JPMorgan Chase or American Express — Isis' launch partners — I had to open an America Express prepaid Serve account to fund the Isis wallet. I’ve been intrigued with Amex’s recent moves to appeal to a mass audience, from allowing users to purchase products with a hashtag via Twitter to targeting gamers with prepaid and digital products.

There was early talk of an Isis Cash card, a Visa reloadable prepaid account, but it looks as though that idea didn't make it to the current wallet.

I linked my PNC debit card to my Serve account as a funding source. I set up the account so that the debit card would be charged if the Serve account and concurrent Isis mobile wallet was used but didn’t have enough funds to cover the purchase.

After loading money into the account, my balance showed an extra $20, “compliments of Isis.” Then I began perusing the offers, which didn’t take long as there were only four on launch day—discounts from mobile carriers AT&T and Verizon and freebies from Jamba Juice and Coca-Cola.

Since the nearest Jamba Juice is more than a mile away, I instead walked a block to the nearest Duanne Reade convenience store. I picked up a Mighty Mango Naked fruit juice smoothie (since I had already become enamored with the thought of a smoothie from seeing the Jamba Juice offer) and walked to the register.

The moment of truth…

With the Isis app running and my Serve account displayed on-screen, I held my phone in front of the contactless card reader.

Nothing.

I tried again — nothing.

Again.

Nothing.

I inhaled, realizing I was holding my breath as other shoppers lined up behind me. Adrenaline surged as I got nervous everyone would point and laugh. “Silly, nerdy girl, my plastic cards work just fine,” they’d say.

Instead of admitting defeat, I asked to try another terminal. The cashier said, "of course," and explained that her terminal's contactless card reader also failed for another shopper earlier in the day.

I stepped to the left, held my phone above the new reader and — voila. In less than three seconds I was holding a paper receipt, the cashier calling the next person to the counter. Perfect.

Because many consumers don’t use contactless payments today, it sometimes takes a while for merchants to notice if their hardware is broken. Such issues will likely become less common if more consumers sign up for Isis, Google Wallet or competing products.

Using Isis was a pretty seamless experience once I got the enhanced SIM card. But most consumers might not want to make that walk to the carrier's store. Even so, it’s less of a hassle than waiting several days to receive a plastic card in the mail.

This process could be eliminated if Isis uses Host Card Emulation, which is enabled by Google's new Android 4.4 operating system, nicknamed KitKat. HCE allows any application to bypass the secure element and make NFC payments. The technology could also be a threat to Isis, since it would allow Google Wallet to operate on the handsets of the major mobile carriers that have refused to support it.

The Isis mobile wallet is available on more than 40 Android smartphones. The enhanced SIM card can be picked up for free at any of the mobile carriers tied to the wallet, and the app can be downloaded for free from Google Play.

While there are thousands of merchant locations that already accept contactless payments (and thus accept Isis), the venture’s next priority will be adding even more merchants to offer discounts through its app.