people in Poland use ssam.
It's regional, I guess.
I'm from central Poland and I always use 'ssę', 'ssie' etc.
There are some verbs with different endings ("-ę" / "-am" opposition in 1st person singular) depending on the area where they are used, for example:
depczę - deptam
głaszczę - głaskam
I've been using "depczę", "głaszczę" for the most of my life, then living in Wielkopolska I found out that the forms like "deptam", "głaskam" are correct too (because at first I thought it's a common mistake in Poznań :)