Point of Sale operating on a wireless network

Does Point of Sale offer a disclaimer that it does not work well on a wireless network? I assisted a new client with the purchase of POS and now she is very upset after four support calls and many hours wasted, she is being told that POS is not recommended for a wireless network. There was no mention of this when the product was purchased.  Support can usually get her logged back in and when we are finished, support thinks the problem is resolved but the next day there is the same issue with logging in. She no longer wants to pay me to make the calls to support as together we have spent  approx. 16 hours on calls and she is ready to return the product..

I don't see any reference that wireless would be an issue with Point of Sale.