Can a GC contact a subcontractors supplier and ask about account information? We have a GC that owes us a lot of money, they contacted our material supplier and asked what was owed on our account. Seems extremely unethical.
I am going to assume this is not a public contract. While asking this may not be ethical, there is no law that would prohibit this.
I hope you have followed the lien procedures to the letter. If they do not pay soon, then reach out to a construction attorney on your options.