Should I need to unschedule my tick method? - cocos2d-iphone

Question

I'm trying to simulate a flick in cocos2d and I need to create a ball every time the users touch is ended, but I can't get the ball to move during the tick method, and I can't destroy the ball (which is a b2body) afterwards without unscheduling the method every time.
- (void) ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
touch = [touches anyObject];
location = [touch locationInView:[touch view]];
location = [[CCDirector sharedDirector] convertToGL:location];
endPoint = location;
force = b2Vec2(endPoint.x - startPoint.x ,endPoint.y - startPoint.y);
if ((force.x != 0) || (force.y != 0)) {
if (ballCount == 0) {
ball.position = startPoint;
[self createBall]; - Here i create the ball every time
[self schedule: #selector(tick:)]; -I schedule the tick method right after the ball is created
[self scheduleOnce:#selector(kick) delay:0]; - This is the only place the ball will launch. For some reason I can't get the kick method to work any where else
}
}
- (void)kick
{
int speed = 30;
float32 setSpeed = speed/sqrt(powf(force.x,2) + powf(force.y, 2));
b2Vec2 ballSpeed = b2Vec2(force.x * setSpeed, force.y * setSpeed);
_ballBody->SetLinearVelocity(ballSpeed);
}
- (void)tick:(ccTime) dt {
_world->Step(dt, 10, 10);
ballData = (__bridge CCSprite *)_ballBody->GetUserData();
ballData.position = ccp(_ballBody->GetPosition().x * PTM_RATIO,
_ballBody->GetPosition().y * PTM_RATIO);
ballData.rotation = -1 * CC_RADIANS_TO_DEGREES(_ballBody->GetAngle());
std::set<b2Body *>toDestroy;
//takes collisions from contact listener
std::vector<MyContact>::iterator pos;
for(pos = _contactListener->_contacts.begin();
pos != _contactListener->_contacts.end(); ++pos) {
MyContact contact = *pos;
bodyA = contact.fixtureA->GetBody();
bodyB = contact.fixtureB->GetBody();
if (bodyA->GetUserData() != NULL && bodyB->GetUserData() != NULL) {
spriteA = (__bridge CCSprite *) bodyA->GetUserData();
spriteB = (__bridge CCSprite *) bodyB->GetUserData();
contactPositionX = spriteA.position.x;
contactPositionY = spriteB.position.y;
if (spriteA.tag == kCurrentItem && spriteB.tag == 8)
{
NSLog(#"contact");
[self removeChild:spriteA cleanup:YES];
[self removeChild:spriteB cleanup:YES];
toDestroy.insert(bodyA);
toDestroy.insert(bodyB);
[self unschedule:#selector(tick:)]; (i unschedule the tick method every time which in turn messes up my other sprites.)
}
}
}
for(std::set<b2Body *>::iterator pos2 = toDestroy.begin(); pos2 != toDestroy.end(); ++pos2)
{
b2Body *body = *pos2;
_world->DestroyBody(body);
}
toDestroy.clear();
}