One other thought before calling the plumber .... Sometimes, "stuff" gets clogged in the toilet that can be cleared with a quality plunger, operated vigorously. The picture below is a crossection of your typical toilet. Notice how things have to ravel to get to the drain .... "stuff" can get lodged in there. The second pic is my preferred toilet plunger. It is vastly more powerful than the cheap "suction cup" version. Feel free to operate it VIGOROUSLY to pull and plunge whatever is blocking your toilet.
You might save $75 in a call to the plumber!