Most companies will notify that they have received your application, but there is not an automated rejection. Call or email the person who made you the written offer.Say that you're following up and want to make sure they received your reply accepting the position. An exploding offer is when a company gives you a teeny tiny window to make a decision of whether or not to take a job offer. Generally it's 24 hours or less. If you don't receive a reply, you could also consider calling their office or contacting someone else in the HR department. Demonstrate your genuine interest in the position. Express your disappointment, but keep it brief and maintain a positive tone. An example phrase to use would be "Hello. Applicants must submit all of the following materials online: 1.