Please restate your question. It makes no sense as written. You're buying a home for $425,000, but have received an offer for $415,000??? The bank is giving $3,600 toward closing costs; gee, that's nice of the bank. But "they" want you to pay $17,000 toward closing costs? The bank does? Or the buyers? Except you said you're purchasing a home.
If someone has made an offer on your home, but is asking you to pay $17,000 in closing costs, then they just want some extra cash. That's a big seller contribution; some loan programs allow generous contributions; some don't. Ask your Realtor what's going on; he or she should be able to tell you.