FNB and Digital Planet

I've been a happy customer of FNB for more than 30 years. Last month I ordered a Garmin watch from them on their Connect packages. We received the watch from Digital Planet, and the unit is faulty. The reason we ordered the watch was because of my son's heart condition and the watch needs to monitor his heart. We are now 2 weeks later, and Digital Planet is not assisting at all. Yesterday I was told that I cannot cancel the contract as we are over the "cooling" period, but the complaint was raised within 5 days after receiving the unit. FNB is only referring customers to their partner (Digital Planet) to have this sorted and we are none the wiser.