All depends on who you are calling. For the most part you need at least two days for reputable 5 star Mn providers. During the weekend most of these providers are with their families, it would be hard to get them last minute.

As far as business being good, I am not sure about this. Just about all of Mn's reputable providers have been advertising on eros lately, usually there are only two or three. My guess is business may not be as good as some providers are letting on!

You started at 4PM, it's a weekend, and it's a holiday weekend so to speak (Father's day.  I'd say the odds were against you.  It's one of those situations where you have to go for a high volume of providers you try to contact to have a decent chance of setting something up.