Hi PamelaNC
Welcome to the forum!
You haven't done anything wrong and it most certainly can be fixed. There are many different ways to treat a spike after the blooms have faded and you will get varying opinions on what to do. Nobody is right and nobody is wrong, just different methods of growing. Sometimes the decision you will make has to do with the condition of your phal after blooming.
I like to let a plant recoup and start growing leaves and roots after a long blooming cycle. I enjoy helping the plant to make new growths besides flowers. I cut the spike down to about 1/2 inch from where it sprouted, all the way off. It is possible some phals will give you a sub-set of flowers from a spike where all the blooms have faded, which is why someone told you to cut it just above the node. I find these flowers to be few in number and and not quite the quality as the full bloom which is why I do what I do. There isn't much harm in trying if your phal is in good condition and not in need of immediate repotting. If the spike begins to dry up, just cut it off and wait for the next blooming season.