In Paul's second letter to the Corinthians, he defended himself against bogus accusations. These false teachers complained about Paul:

"He's not a real apostle."
"He is fickle."
"He appearance is deplorable."
"His speech is contemptible."
"He can't get churches to financially support him."
"He doesn't carry letters of recommendation."
"It is obvious God is not blessing him because of all the suffering he endures."
"He is holding you back."
"He's bossy."
"He's crazy."
"God doesn't speak through him."
"He doesn't love you."
"He is cheating you."
"He doesn't have the authority to tell you what to do."

These enemies of Paul were probably the Judaizers who stalked him throughout his travels. They tried to inject law into the gospel and that's always a bad combination.

Since Paul, the greatest missionary of all time, had critics, we should not be surprised when people complain about us also.