How to cancel in-app purchase made flutter ios

Question

I am using in_app_purchase package.

I have created a free package with a price of 0.00 in the "in-app purchase" section. also, I have created a recurring package of 0.00 in the "subscription" section as the "in-app purchase" section does not allow me to create the recurring package.

but the issue is, how do I cancel the active package?

I tried changing the package from recurring to free package as a cancel. But when I try to buy the recurring package again, it shows you have already bought that package.

how to solve this issue?

P.S. I did find a few answers in the StackOverflow but none of them answers my question

/// Buy package using in-app purchase
Future<void> buy(Package pkg) async {
    try {
      if (!Platform.isIOS) return;
      final bool available = await iapInstance.isAvailable();
      if (!available) {
        throw ('In app purchase not available');
      }
      final ProductDetails productDetails = state.iapProducts.firstWhere(
          (e) => e.id == prefixedSlug(pkg.slug),
          orElse: () =>
              throw ('Selected package not available in IAP at the moment'));
      await iapInstance.buyNonConsumable(
        purchaseParam: PurchaseParam(
          productDetails: productDetails,
          applicationUserName: '${authCubit.state.authUserModel.user.id}',
        ),
      );
    } catch (e) {
      print('=> buy() Error: $e');
      emit(state.copyWith(isProcessing: false));
      rethrow;
    }
  }
  
  
/// returns the slug with the app package identifier as the prefix
///
/// DEV: free => com.example.dev.free
///
/// PROD: free => com.example.free
String prefixedSlug(String slug) {
    final String prefix = PackageInfoUtils.packageInfo.packageName;
    return '$prefix.$slug';
  }