To the OP,
Since you are new here, and that's fine, I'll repeat what I was told in Steward school:
There only two kinds of grievances.
1) Where you think there has been a contract violation by the company. You file,
the burden of proof is on YOU to prove there has been a violation.
2) Where there has been disciplinary action on the part of the company. NOW, the
burden of proof is on THE COMPANY to prove the discipline was warranted.
In other words, you were terminated by the company. THEY have to prove, beyond a shadow of a doubt that their case is warranted. THEY have to prove that they did not receive your calls or messages (you DO have a record of them, don't you?). THEY have to prove that THEY did not record them on a different board to make them disappear. THEY have to prove EVERYTHING they claim in order to terminate you.
BUT, YOU have to rely on your Stewards and BA (Business Agent). Good luck.