This happened to me, too, with Home Depot. I was buying a dryer and planning to do the six months interest free. They tried to get me to apply for another one, and I told them I would shop at Lowe's instead. I had had the card more than 10 years.
I called customer service and complained. They said it was their policy not to notify you when it was cancelled b/c it hadn't been used lately. Absolutely ridiculous policy IMO.
I have a Sears card that hasn't been used in three or four years. I'm assuming it's still open since I get offers from them once in a while.
I'd check on that. I went to buy a grill on line and they said it had been cancelled. They said they cancel cards after 2 years of inactivity.