You might do best if you contact Lowes, and ask about tech support. The weight of the door will govern the method of attaching the hinges, regarding screw size. If the door, or the door frame, has been splintered, or if the existing holes are enlarged, you should be able to fix this condition by first filling the hole with epoxy paste, and then inserting the screw.

are you sure they are #8? #10 is more or less standard for door hinges. Since Reliabuilt assembled the door and frame, they should know better.
The 3/4" or 1" long screws that come with most door hinges are just fine for most hardwood doors. They are not adequate when screwing into a softwood frame or a softwood door. Worst case is when you mount a heavy hardwood door into a softwood frame. But even a softwood, steel, or fiberglass door is frequently too much for these short screws. all of those types of doors use wood (usualy pine or fir) on the edges to screw into.

You can probably replace the screws easier than you can get a response from reliabuilt or home depot. replace the ones going into the door also. Put some blocks under the open door to take the weight off the hinges and replace the screws one at a time. 1 1/2 #10 is apropriate.

If it was me, I would be inclined to take the whole unit out and return it to home depot just for spite!