One option is to send a letter notifying them of your pending patent application.  Reputable businesses are likely to respect your patent rights and will want to avoid a possible infringement suit in the future.  This can be particularly useful if your application is published.  If you send them a copy of your published application and a patent subsequently issues with similar claims, you may later be able to get damages for infringement during the time period between when you notified them of the application and when your patent issued.

Talk to your attorney for more details and for the proper wording of the letter for your situation.  In some instances, the best solution may also be to do nothing and bide your time until the patent issues.