school called Glossa.pl
Here are the references to it on this forum:- ?phrase=glossa+language+school
Unfortunately what you will find on this forum are people claiming to have attended their courses and giving them glowing reviews ( usually people who work for said school ), this is not unique to Glossa though, other 'students' of different language schools crop up on this forum quite often too. It is a bit of a minefield trying to work out which schools are genuinely good and which aren't.
What they all have in common though is that they are quite expensive.
Have a look at this thread which gives some opinions about 2 week intensive Polish courses:-https://polishforums.com/study/opinions-weeks-intensive-course-48381/