My iPhone 4 becomes very slow after upgrading to IOS7

My iPhonel 4 becomes very slow after upgrading to IOS7

i did every tricks might help like disabling Background Apps and turning of Documents and Data syncing in iCloud also Increase Contrast and restoring it to factory default....

it's still very slow in any action needed also there is a lot of bugs when using it like canceling the call but it's not apprearing in the lock screen or it appears but when sliding it it's opening another notification... touch is very laggy ..

Apple Please we need help