I'm not able to understand. How exactly did they figure out that you elicit with escorts when you visit canada?
Phone numbers of escorts in your phone. They ask how do you know this person?
They may have her real name on file along with her work name and work number.
How you answer will tell them if you know her as a friend or customer.
Even if you delete data, there is software that recovers deleted files. Eg pictures and video.
Large amounts of cash are instant red flags for both borders.
Border agents on both sides have much broader power of search and seizure and detention than police. It makes sense given their mandate.
Regardless of your rights, they will pretty much do whatever they want with your devices.
They know they cannot use certain things in court but they will still look.
Always remember the agent may have just finished dealing with ten assholes in a row. You might exactly match the profile of a guy they caught an hour ago with a bunch of contraband. Or you might be completely innocent but linked to a person of interest.
Never try to fool them or outsmart them, they deal with liars all day and can tell right away.