Expired Visa and Immigration office rant…

Hey, I am a masters student. My visa expired on march 15th.

Feb 24th i had my residence permit appointment telling me they are gonna start processing the RP and will let me know about the visa in few weeks.

But still there is no response from them!!

I mailed them so many times but still there is no response

I wanna travel to berlin but having doubts regarding this gonna be a issue if train attendants check me ( i have valid d ticket).

So is it okay to travel under this circumstances ????

(The immigration gave me a paper that has a pin like for online purpose. Chat gpt told me its only useful after i receive my residence permit)