Has the guy who installed it partially blocked the plug and waste with the silicone he sealed it to the sink with? unscrew the trap from the waste and check from the downstream side.
sorry wrong post. but should be screwed to the wall, bracket supports the weight, (right size) screws fix it in place. make sure you have something in the wall to drive the screws into, noggin for example. if not I would either open the wall to put one in or use no more gaps between the porcelin and the wall.
sorry wrong post. but should be screwed to the wall, bracket supports the weight, (right size) screws fix it in place. make sure you have something in the wall to drive the screws into, noggin for example. if not I would either open the wall to put one in or use no more gaps between the porcelin and the wall.