Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble, Maxine.
Your system can accommodate up to 6 cordless devices total (handsets, range extenders, key finder, etc).
You may purchase a new handset here: http://amzn.to/1PKtsRt
However, you would have to purchase this on your own, it is not free and panasonic would not provide it for you.
If what you purchased at the store is incorrect, that is the responsibility of walmart, not panasonic. You should not have to pay for another, and would be better off returning the system to walmart directly and insisting that they provide you with a new system. If they won't help you, then take it up with your credit card/bank.
Now, if you actually bought the 6572 system, that would come with only 2 by design.
If that model number ended with a 3, it should have 3.
If you can return it, and they don't have other systems there, you'd be better off starting over with a different model, that has 3 to begin with. It is always cheaper to buy a bigger package up front than to add individual pieces later: http://amzn.to/1PKtsRt would be a recommended alternative model (what you bought is actually a 5 year old model)
I am an independent technician and I've spent my personal time, unpaid, in an effort to assist with the question for which you solicited my services. This site works on the honor system, and to that end, I have prioritized working with you ahead of other paying customers.
Although you’ve already paid your fee to the site, I am only compensated for my efforts when customers such as yourself leave positive feedback for my work. Again I apologize there is not a better outcome here, though this is really beyond either of our control. I do hope you’ll consider leaving a 5 star rating for me, rather than “shoot the messenger”, so that I may get credit for my time spent in good faith to answer your question accurately.