Without knowing your specific issues, it's impossible to diagnose the reasons for the delay. You should contact your loan officer (if they even give you one) to find out how far you are from closing. Moving to another lender might cause more delays, especially if you are only a few more days from closing.
The only comment I can say for sure is that most Realtors would prefer you to work with a local lender rather than a bank. Banks are just too slow these days. Great for checking accounts, but poor on mortgage service.
Licensed Mortgage Loan Officer