Various Glitches With In App Purchase (iOS) - ios

Question

I've been experiencing various glitches with in-app purchases. Here are a few.
When I tap an item to buy it, it shows the Confirm you In-App Purchase alert and then after a second or so, it closes it self and opens the login alert.
Some times I'll log in, then it will ask me to log in again. Alerts pop up and go away on their own and it looks very glitchy. Some times the app crashes with no error message.
I haven't been able to search for any answers because these issues are quite strange.
Here is the code I'm using (I'm using a class named Game and a category names Game-Resources)
Game.m:
- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response{
product = response;
}
- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions{
if (purchasing == NO){
// if I don't put (purchasing) in, this method is run multiples times
purchasing = YES;
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
for (SKPaymentTransaction * transaction in transactions){
switch (transaction.transactionState) {
case SKPaymentTransactionStatePurchasing:
NSLog(#"purchasing");
break;
case SKPaymentTransactionStatePurchased:
purchasing = NO;
NSLog(#"done");
if ([[NSUserDefaults standardUserDefaults] objectForKey:purchaseNSUserName] != nil){
int i = (int) [[NSUserDefaults standardUserDefaults] integerForKey:purchaseNSUserName];
[[NSUserDefaults standardUserDefaults] setInteger:i + purchaseNSUserAmount forKey:purchaseNSUserName];
[[NSUserDefaults standardUserDefaults] synchronize];
}else{
[[NSUserDefaults standardUserDefaults] setInteger:purchaseNSUserAmount forKey:purchaseNSUserName];
[[NSUserDefaults standardUserDefaults] synchronize];
}
[[SKPaymentQueue defaultQueue] finishTransaction:transaction];
break;
case SKPaymentTransactionStateRestored:
purchasing = NO;
break;
case SKPaymentTransactionStateFailed:
purchasing = NO;
if (transaction.error.code != SKErrorPaymentCancelled){
[[SKPaymentQueue defaultQueue] finishTransaction:transaction];
//error happened
}
break;
case SKPaymentTransactionStateDeferred:
purchasing = NO;
break;
default:
break;
}
purchaseNSUserName = nil;
purchaseNSUserAmount = 0;
}
}
}
In the ViewDidLoad:
if ([SKPaymentQueue canMakePayments]){
self.productsRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:[NSSet setWithObjects:#"somethinghere", #"anotherthing", nil]];
self.productsRequest.delegate = self;
[self.productsRequest start];
}
In Game-Resources (when buy button is pressed):
SKPayment *payment = [SKPayment paymentWithProduct: product.products[productID]];
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
[[SKPaymentQueue defaultQueue] addPayment:payment];