So many people misunderstand science. Science deals in theories supported by observations. If you are looking for irrefutable truths, turn to religion.
If there are observations that contradict a scientific theory, then that theory will eventually be abandoned.
Black holes and the big bang theory fit with a vast body of observation evidence. Different theories may well emerge in the future that better describe the observations but at present there is no significant observational evidence to contradict either the General Theory of Relativity or the Big Bang theory.
People who endorse scientific theories as fact really don't understand science. Science attempts to describe nature. If nature doesn't fit with the theory, the theory is wrong. This is why science evolves over time as new and more powerful theories emerge.
My two cents
Have fun,
Doug