Introduction
To use Mobile Service Cloud and get the contact tab on your store, you have to place a piece of Javascript on your store.
Resolution
Make sure the Javascript is in your template before the closing body tag. For more information about placing the Javascript vistis our developers page: https://developers.cm.com/mobile-service-cloud/docs/introduction
The following script should be added:
<script src="https://selfservice.robinhq.com/external/robin/[YOUR API KEY].js" async="async"></script>
You can find your script by navigating to: Settings → Contact tab