Black holes do not make matter "disappear"... they just convert it into the most basic of matter, energy.
energy is an atom in motion,
so If everything 'disappear', all will be left are atoms.
atoms... every atom has it's own gravitational field.
gravitational force has infinite range, regardless how tiny it is.
all the atoms in an empty universe will attract each other, which will transform into energy, and when atoms are squished to a point, they perform molecular bonds.
given enough time it could cause another Big Bang.
Heh~ Maybe.
It has to end someday!