In the singular the noun linoleum is remaining as it is in all cases.
In the plural it takes the suffixes -a, -ów, -om, -a, -ami, and -ach.
(Compare an article about the word exemplum in pwn.pl/poradnia and an article about the noun akwarium in WIKISŁOWNIK.)
It is difficult for me to find a context, in which I would use a plural form of linoleum as it is a type of floor covering, a material.
I have never heard anybody say "linoleumu or linoleumem", not seen it in print either. It must a very special group of people speaking substandard Polish that use such forms.
By the way, "odmiana rzeczowników" translates to English as "inflection of substantives", not "change".