If you pull the globe out and look at the bottom of it where the wax is, can you see the heating coil sitting flush on the bottom? (see attached picture). If it is, you may just need to run the lamp for a little longer then 2 hours to melt it a little more and then shut it off for about 4-5 hours. Once your turn it off the lava should be warm enough that it will settle down at the bottom a little better. Try doing this for about 2 or 3 days so all of the wax coagulates at the bottom again. Run the lamp for 4 hours on the 4th day and see if it starts bubbling up like normal.
If the coil is not sitting flush on the bottom, (could be on the side or at an angle) run the lamp for about 3 hours to get the wax nice and hot. Then pull the globe out using some oven mits or oven pads and put it on a table or something sturdy, preferably with a towel underneath so you dont burn the table (hold on tight so it doesnt fall and the wax gets shaken up).
Find the coil and SLOWLY turn the globe at an angle and TAP it lightlyon the sides of the bottom so the coil falls flush to the bottom,or as close as possible.
DO NOT WHACK IT OR SHAKE THE GLOBE THIS WILL RUIN YOUR WAX
Once the coil is back at the bottom of the globe put it back on the base and let the wax cool for about 4-5 hours. Turn your lamp back on and it should start bubbling up as normal.