Great new product idea - but poor quality

I was given the opportunity to test this product for free. I was excited to try it, because I don't like my car air fresheners to be in the vents, cannot hang them off my rearview mirror, and I don't like them just 'loose' in the car. So this was terrific, as I could just plug it into my 'lighter port' - that never gets used anyways - it's out of the way, and gets used ONLY while driving (to have it last longer). While I don't like the perfume scented ones - the fruity ones are amazing. My only issue was trying to find a replacement insert afterwards. They didn't become available in my area for about 2-3 months later; and even then, only by buying a new starter kit. The next one we bought, the scent insert didn't work. So we gave up on it.