If the lender won't talk to you, you can check the deed records. There should be a deed filed in the next couple of weeks, that will reflect the sale, which was most likely to the mortgage company. Alternatively, the buyer is likely to contact you in the next couple of weeks, so I doubt you will have to wonder for long. Finally, if the property was not sold, you will most likely receive another foreclosure notice this week, for the April sale.
If you received the foreclosure notice, you should assume that the property was sold.