I just finished my final papers on my house and?

That was the recording everything. and I was suppose to get my keys the next day. its been four days now. My lender got the listing agent on this because I guess the problem is everythingis odne on my side but Bank of America(the sellers bank hasnt approved it yet, or something like that. I hope its today I get my keys. Does anybody know why the delay? I would figure it cant be that long if they have my closing on the papes with a notary there. but like I said its the sellers side. the bank hasnt approved it yet.