unfortunately i think this needs some skills 😀

fire up the terminal.

dpkg -l|grep libreoffice; # search for all installed packages with that name

# you will have to compile your own list and run something like that:

apt-get remove -y --purge libreoffice-common;
apt-get remove -y --purge libreoffice-java-common;
apt-get remove -y --purge libreoffice-style-galaxy;
apt-get remove -y --purge libreoffice-style-tango;
apt-get remove -y --purge libreoffice5.2;
apt-get remove -y --purge libreoffice5.2-base;
apt-get remove -y --purge libreoffice5.2-calc;
apt-get remove -y --purge libreoffice5.2-debian-menus;
apt-get remove -y --purge libreoffice5.2-dict-en;
apt-get remove -y --purge libreoffice5.2-dict-es;
apt-get remove -y --purge libreoffice5.2-dict-fr;
apt-get remove -y --purge libreoffice5.2-draw;
apt-get remove -y --purge libreoffice5.2-en-us;
apt-get remove -y --purge libreoffice5.2-impress;
apt-get remove -y --purge libreoffice5.2-math;
apt-get remove -y --purge libreoffice5.2-ure;
apt-get remove -y --purge libreoffice5.2-writer;

# keep copy pasting that into your console until it keeps saying:

E: Unable to locate package
E: Unable to locate package
E: Unable to locate package
E: Unable to locate package
admin