I am using Microsoft Bings ads .NET library version V13.
Currently I am able to upload form leads which has MicrosoftClickId using OfflineConversion array in ApplyOfflineConversionsRequest through CampaignManagementServiceClient.
As per https://docs.microsoft.com/en-us/advertising/campaign-management-service/offlineconversion?view=bingads-13 , The MSCLKID for the offline conversion is required. Our system uses a third party call tracking system CallTrackingMetrics and we do not have MSCLKID .
How can I upload my call conversion data ?