The word assume has too many funny cliches attached to it to use for this post, so presume is the word of choice.
Presuming is to assume with expectation and confidence, but without evidence.
It’s a big mistake to presume anyone you want to reach in business can or will:
Accept a text message
Listen to music on every conceivable platform out there
Take a screenshot
Answer a call before business hours
Attend a business meeting well beyond business hours
Open any number of file styles you may send
Wait indefinitely until you make a decision
It’s really a mistake to presume much of anything, but when it comes to good manners, common sense and techie stuff, it’s in your best interest not to.