2450 zł netto
At that rate, there is little reason for you to be in Warsaw at all. And it is unlikely that they will substantially increase your pay, as you have already demonstrated that you are willing to work for peanuts.
Do you guys think this is a realistic reqeest? Or do you think it is not realistic and should not even think about it? Friends of
mine earn almost double what I earn.
Without knowing your qualifications and experience, it is impossible to say whether your request is realistic or not. It doesn't matter what your friends earn. It simply has zero relevance to your case.
and I do not want to leave my company because I love my team and work!
You will have to leave if you are only making 2450 zł netto. The only possible reason to stay for that pay is to get experience and have fun slumming it as a poor recent graduate. And experience in working for a call center means very little on the job market unless you have an outstanding proven sales record or substantial managerial experience. As an ordinary call center worker, you might as well be flipping burgers or stocking shelves at the supermarket.
Also, in "customer service", which I understand as "call center", the most difficult and unpleasant jobs (cold-call sales) are the ones that are paid the lowest. Companies relocate customer service jobs to countries like Poland specifically so that they can pay very low wages. That is their primary incentive.