Very well said, Mark! (and everyone else who contributed)
I called my doctor's office on this and they never even HEARD of a magnetic mattress!
So, as been said, a magnet is a magnet, and any variation of such is TABOO for anyone who has an SCS, pacemaker, etc., so case closed.
And, you guessed it, the 'sleep on it' clause (or 'cool down period', as another friend put it) was a whopping 72 hours, of which has elapsed already, so to pursue this any further I spose would require a law-suit of sorts. I'm sure the legal fees would overshadow that of the cost of this purchase (of which I am too embarrassed to disclose

)
So, the next step will be to decide if DH can keep his mattress and I sleep elsewhere....or else take the chance of sounding unappreciative of his gesture.
This, I reckon, is more of a "Dear Abby" issue
I'm certainly open for any further suggestions.
Meantime, I'm gonna go stick my head in the sand