one letter doesn't make a difference if it is understood they are one and the same person. If you were verbally told your friend, no matter how her name is spelled, was not allowed on the premises and it was followed with a notice using the misspelled name, you knew who it referred to. Playing the "I didn't know because you spelled it Billy instead of Bill" won't cut it.
If you want to dispute the eviction, you can argue it to the judge.

