Were you just calling him to talk to him, like get a feel of his energy, or did you call him, ask for him to help you with something and it didn’t manifest?
Also, sometimes when we call on spirits, it may feel like they aren’t there or listening, but they really are there. We just have to develop our senses in order to feel or hear them.
When opening the sigil, have you tried using the method in the below link?
You can also petition him using a petition spell. It’s easy and effective: