People complain to me about not being able to get in touch with their old bosses. This means they are talking about business owners.
I have not heard of anybody having problems like that with their former supervisors from large companies. After all, those people are subordinates of their own bosses too. Unless you have spat into his coffee mug or slept with his wife, the two of you should still be on good terms.
It's a different story with Owners/CEOs. Some may ask, why do you want to be in touch with them? As the matter of fact, for many reasons. I've already addressed the references issue (see my post from a month ago CFO's References Trap). He (I am talking about an archetypal boss now) may have a networking connection you crave. He may know someone you need to contact for your new business. You liked his attorney and now you need one.
There could be a million reasons. But you cannot reach him. You emailed, you left messages with his assistant and/or wife, you tried to contact him via mutual relation... No response! And that fucking hurts!
You have toiled 60-hours a week for him, you grew his business, you made him richer, you saved his ass from troubles numerous times. Hey, you pulled him from the verge of bankruptcy and complete destruction! Hell, it's his fault you are not his CFO/Controller anymore. You are the one who should be mad at him!
And the funny things is - other people who worked there adore you. They tell you how great and important you were to the entire company, how much they've learned from you. Yet, the person who benefited the most from it, doesn't even want to acknowledge your existence.
Now, let's put emotions aside and think about it with our cool, rational financial minds. There are obvious reasons for your ex-boss to be mad at you:
1. You warned him about troubles that may befall his business and did your best trying to cover the risks, but he didn't listen to you. Now, history proved you right. Do you really expect him to talk to you and acknowledge that?
2. Even before your ways parted, subconsciously he knew your were the smarter one. Secretly he hated you for that.
3. In his mind he expects to hear, "I told you so." He has no clue that your decency would never let you do that.
4. If he contracted and managed to save the smaller version of his business, in his head he probably blames your absence for his inability to grow back.
5. He had to hire three people to replace you and still they cannot keep up. Whose fault is that? Yours.
6. And that secretary of his... Well, let's not go there.
If any of these scenarios apply to your case, I guarantee, he will never talk to you, even if he needs you desperately. He is the BOSS - he cannot put the ego aside the way we always do.