How to set number of payments or end date for Schedule

I have been trying to setup a Schedule based on https://developer.heartlandpaymentsystems.com/Ecommerce/Recurring using a a tokenized credit card. I have managed to create a Schedule, but it never has an end date, nor a number of payments. I am using version 8.0.2.

What is the right way to set it up?

Here is the code I am using (I am changing the Schedule id on each request):

$schedule->id = 'S-20231030';
$schedule->customerKey = $customerKey;
$schedule->paymentKey = $paymentMethodKey;
$schedule->amount = 100;
$schedule->currency = 'USD';
$schedule->startDate = Carbon::tomorrow();
$schedule->paymentSchedule = PaymentSchedule::DYNAMIC;
//$schedule->endDate = $end_date;
$schedule->numberOfPaymentsRemaining = 4;
$schedule->frequency = ScheduleFrequency::WEEKLY;
$schedule->reprocessingCount = 1;
$schedule->emailReceipt = 'Never';
$schedule->status = 'Active';

$response = $schedule->create();

I haven't found a way for making $schedule->numberOfPaymentsRemaining nor $schedule->endDate = $end_date work.

Sometimes I get schedules created, like the following:

GlobalPayments\Api\Entities\Schedule {#2246 ▼
  +amount: 100
  +cancellationDate: ""
  +currency: "USD"
  +customerKey: 165162
  +description: null
  +deviceId: 6392739
  +emailNotification: false
  +emailReceipt: "Never"
  +endDate: ""
  +frequency: "Weekly"
  +hasStarted: true
  +invoiceNumber: null
  +name: null
  +nextProcessingDate: DateTime @1699194998 {#2247 ▼
    date: 2023-11-05 14:36:38.0 UTC (+00:00)
  }
  +numberOfPaymentsRemaining: null
  +poNumber: null
  +orderPrefix: null
  +paymentKey: "d97b570e-4c5b-4c41-a80b-6a493341feca"
  +paymentSchedule: "Dynamic"
  +reprocessingCount: 1
  +startDate: "10292023"
  +status: "Active"
  +taxAmount: 0
  +productId: null
  +customerNumber: null
  +scheduletext: null
  +id: "2023-10-28T20:58:40-abeeworks-S-1-5156"
  +key: 51532
}

Many other times I get errors like

GlobalPayments\Api\Entities\Exceptions\GatewayException {#2188 ▼
  +responseCode: null
  +responseMessage: null
  #message: "Status Code: 400 - Unable to add payment method: Host Unavailable "
  #code: 0
  #file: ".../vendor/globalpayments/php-sdk/src/Gateways/RestGateway.php"
  #line: 107
  trace: {▼
    .../vendor/globalpayments/php-sdk/src/Gateways/RestGateway.php:107 {▶}
    .../vendor/globalpayments/php-sdk/src/Gateways/PayPlanConnector.php:176 {▼
      GlobalPayments\Api\Gateways\PayPlanConnector->processRecurring(RecurringBuilder $builder) …
      ›     $this->mapUrl($builder),
      ›     $request === [] ? '{}' : json_encode($request)
      › );
    }
    .../vendor/globalpayments/php-sdk/src/Builders/RecurringBuilder.php:75 {▼
      GlobalPayments\Api\Builders\RecurringBuilder->execute($configName = 'default') …
      ›     $client = ServicesContainer::instance()->getRecurringClient($configName);
      ›     return $client->processRecurring($this);
      › }
    }
    .../vendor/globalpayments/php-sdk/src/Services/RecurringService.php:14 {▼
      GlobalPayments\Api\Services\RecurringService::create(RecurringEntity $entity) …
      › $response = (new RecurringBuilder(TransactionType::CREATE, $entity))
      ›     ->execute();
      › return $response;
    }
    .../vendor/globalpayments/php-sdk/src/Entities/RecurringEntity.php:36 {▼
      GlobalPayments\Api\Entities\RecurringEntity->create() …
      › {
      ›     return RecurringService::create($this);
      › }
    }
  }
}

Here are my questions about the integration:

How am I supposed to set either the number of payments or the end date?
Why is the "Host Unavailable" error thrown? Is there a rate limit? Is there something else to consider?
What timezone are the start date and end date supposed to use?
Once a schedule gets created, is there a way to process the first payment right away? Or will the first payment be processed the next day the sooner?
Once a schedule gets created, is there a way to access information about the last payment processed? I see a paymentKey in the response. Is there an endpoint that can be used to get more information about the payment?
How are we supponsed to acknowledge that a payment was processed? Should we constantly query Schedule::findAll() or Schedule::find()?

globalpayments / php-sdk

How to set number of payments or end date for Schedule #121