How late is customer service desk open?

It can vary store to store and also depends on if they are staffed well enough to have someone in that position. If you need customer service, any service manager can do a return/exchange at their discretion. You can't make anyone do anything, so be nice, and you'd be surprised what they are capable of. I once purchased a product for my car stereo and as soon as I walked out, I realized it was not the right product. Even though it was 10:00 at night and the store was closing in an hour, the service manager opened a register and accepted the return. Like I said be nice 🙂

Yes you are correct. the staff is polite and helpful