Innocent,
You allude to the contract you signed and what was written on it.....
When has the company ever abided by your contract. I can't even count that on one hand!
An increment is a contractural rise and even you admit one year they didn't pay it. That means they went against the contract. A bit like 42 days of leave. We are lucky now to get 30 of which half is normally now allocated.
In the end the rise in money you get from year to year is the same whether you call it an contractural increment or a pay rise. Honestly who gives a *%#+!