How do I restore my contacts from the cloud
Lost my contacts on my iPhone, can I restore them from the cloud?
Were you storing them on iCloud?
They don't automatically save there, unless you had the Contacts option turned on in iCloud settings, and were using the iCloud group when creating contacts.
Signing in to iCloud on your phone again, should have put them back if they were stored there.
If you were only storing them on the iPhone's storage, then there's no way to get them back.