Typically, if you what to use copyrighted music in your project, you must obtain two licenses - a Sync (Synchronization) license from the publisher and a Master license from the recording label.
Corporate cost-cutting and new technology have resulted in the advent of automated systems that can make the on-hold experience even more frustrating. It can feel near-impossible to get a human on the phone these days, which a national survey conducted by Consumer Reports found to be Americans' second-greatest annoyance, after hidden fees but beating out inaccurate weather reports and dog poop. Green observes that often people call as a last resort, because something on the website wasn't clear, perhaps, and they really need an answer quickly. So callers are captive listeners, a state often associated with the gridlock of waiting, whether in line at a Starbucks, in a dentist's chair, or in the proverbial elevator making its slow way up.

“I received my recording the next day, and was extremely impressed by the quality, not to mention the price." Madeleine Levy, theholidaymatchmaker
It’s very important to thank your customers for waiting. Being on hold is not a desirable experience for anyone. The least you can do it thank your clients for their time and to help them not feel neglected.