Well, I think the last time an iphone was successfully hacked the budget was around $1M if I remember correctly (?). So basically, just reset it and you're done. Unless what you had on there was worth $1M or more.
Remember the data stored on an iphone is encrypted. So thats what I am saying, its impossible to get to the encrypted data, or virtually impossible, unless you pay a lot of money. Or unless you are apple of course - but again, why would Apple go to the trouble of trying to restore deleted data from your phone? They wont even do it for federal government.
So just to clarify, all data on your iphone is encrypted. Its accessible only once you have authenticated via the phone itself. If you reload the phone, that data is effectively gone. Even if you get onto the storage chip itself and recover deleted data, it will be encrypted and you cant read it unless you are apple, or someone with a big budget.