Hi
Normally, the partner you bought the license keys would/should be able to provide you with the following Post Order:
EG:
Meraki order number: 5s3xxxxxx
Dashboard License Key Numbers: Z2Ax-xxxx-xxxx
Single Cisco Order Number: 1079xxxxx
If you log an e-mail support ticket to:
licensing@meraki.net
And provide that those details as provided above, then they will be able to help.