The toilet will flush but the water does not go down for hours. The last few days when I use the shower the water starts bubbling in the toilet and now the water in the shower won't go down .this is a new house and the plumber said we had bought a cheap toilet.

The bubbles are caused by drainage hitting a partial blockage and sending a bubble of air bouncing back. This can be addressed in one of two ways.
1-pull the toilet and snake the line from there, or
2- snake from the lavatory roof vent. Put out enough snake to reach the base and 15 for more. Good luck, Tom