getMCACustomersFromBillingAccount.ps1

# Retrieve all customers that your Billing Account has access to

# Authenticate to Azure
$azContext = Get-AzContext
$azProfile = [Microsoft.Azure.Commands.Common.Authentication.Abstractions.AzureRmProfileProvider]::Instance.Profile
$profileClient = New-Object -TypeName Microsoft.Azure.Commands.ResourceManager.Common.RMProfileClient -ArgumentList ($azProfile)
$token = $profileClient.AcquireAccessToken($azContext.Tenant.Id)
$authHeader = @{
    'Content-Type'  = 'application/json'
    'Authorization' = 'Bearer ' + $token.AccessToken
}

$restUriBillingAccounts = "https://management.azure.com/providers/Microsoft.Billing/billingAccounts?api-version=2019-10-01-preview"

# Retreive the Billing Accounts you have access to
$restUriBillingAccountsResponse = Invoke-RestMethod -Uri $restUriBillingAccounts -Method Get -Headers $authHeader

# Filter Billing Account Name for the Microsoft Customer Agreement / Partner
$billingAccountName = ($restUriBillingAccountsResponse.value | Where-Object { $_.properties.agreementType -like "MicrosoftCustomerAgreement" }).name

Write-Host -ForegroundColor green "Retrieving customers for billing account" $billingAccountName

# Get Customers that your billing accoutn has access to
$restUriCustomers = "https://management.azure.com/providers/Microsoft.Billing/billingAccounts/$billingAccountName/customers?api-version=2019-10-01-preview"
$restUriCustomersResponse = Invoke-RestMethod -Uri $restUriCustomers -Method Get -Headers $authHeader
$customers = @()

$customers += $restUriCustomersResponse.value

# get the nextLink and request content
$customersNextLink = $restUriCustomersResponse.Nextlink

# Do that magic until there is no more Nextlink received
    while ($customersNextLink) {
        $nextlinkResponse = Invoke-RestMethod -Uri $customersNextLink -method GET -Headers $authHeader
        $customersNextLink = $nextlinkResponse.Nextlink
        $customers += $nextlinkResponse.value
    }

# Return the customer name
$customers.properties.displayName

Write-Host -foregroundcolor green "API Returned" $customers.count "customers"