Go to icloud.com on a computer, sign in, open the Contacts app and make sure your contacts are indeed there.
If not, check Settings > iCloud on your iPhone 4S and make sure you have Contacts turned on for syncing. If not, turn it on, choose Merge if an option is offered.
Wait a while then go back to icloud.com and make sure your contacts are now there.
If the contacts are in icloud.com:
Go to Settings > iCloud on the iPad and make sure you are signed into the same account, and that your Contacts are turned on.
Good luck.