Help deleting old Apple ID on Iphone 4 and other things?

I bought off my brother in law's iPhone 4 and tried to erase and overrite his old Apple ID so I was abled to log into mine and buy/download apps. Now with some updates like Pandora and other ones that were already on the phone need to be updated but when I try to update them it ask for the first person's ID which is a guy who sold it to my brother in laws before me.

Is there a way I can update them on my ID?

Also when I'm trying to download my purchased songs from the Itunes via phone it won't let me because I get a pop up that says " (song name) could not be downloaded at this time. Please try again later" It always does that. Much help would be appriciated.

Oh and just in case, it's Jailbroken.

Jailbroken may be the issue, can't be certain. You can't update the apps on your own Apple ID if they were installed on a different one. You have to delete them and install them again on your own. And if they were purchased for cash on his, then too bad you'll have to buy them again under yours!
As a side note, if its really bothering you and you decide to sell it, try http://www.cashiphone.com instead of listing it on eBay for weeks. You even get free shipping so they're cool.