Apparently their complaint and planned march to moscow was because one of their bases in Ukraine had been bombed by russian forces. So they were marching to protest to the head of russian military against the bombing and injury to wagner fighters. Moscow has agreed to absorb wagner and all autonomous private fighters into the russian military so as to have unified command to improve efficiency in fight against ukraine.
Wagner are happy that their grievances have been addressed and they are back to their frontline bases in Ukraine to continue with their attacks on Ukraine.