Unable to remove my hose pipe ( garden hose ) from the tap ( hose bib )
A spanner like straight jaws will not hold a round fitting well. 

You need a pipe wrench or adjustable water pipe pliers with curved jaws. 

These pliers adjust to hold the fitting without two much damage and are a basic tool all home owners or some one that lives in a home should have.

Make sure you are turning the correct direction, this may sound silly but after teaching scuba I was amazed how many folks could not turn on or open a valve because they were turning the wrong direction. 

To remove the hose turn the fitting counter clockwise , I used to tell my students put your thumb on the top turn right to close or tighten OR turn left to open or loosen. “Righty tighty lefty loosy.