"To rectify the matter" means to resolve or fix a problem or issue. It is about taking action to correct something that went wrong or to make things right again. Full definition
Countries that recently have been neoliberalized may still rectify matters by taxing rent and windfall gains to recover what has been appropriated or is newly created by infrastructure investment. (michael-hudson.com)
Glad to see you not only rectified the matter but also gave us all the option to read it. (justarsenal.com)
«We are taking all reasonable action to minimise any harm caused and to rectify matters where we can.» (bbc.com)