Spring sensor sale and customer service

I received an email about spring sale of 15% off of sensors that would be applied at checkout.  It said that it expired on 4/29.  I ordered a couple of sensors today (4/29) and when I checked out the discount was not applied.  I called customer service and was told that the sale ended at 9PM (not stated in the email).  I canceled my order.  It seems that you are not interested in selling sensors! Customer service was no help!