Pension rights change after redundancy

I worked in Ireland for a french multinational for 7 years in a permanent position. They had a defined benefit scheme of which I was a member. I also paid some avcs.
I was made redundant a number of years ago. as the facility closed. There was no mention of coverting the pension entitlement into a retirement bond. I expected to receive a defined benefit pension at 65 in proportion to my length of service.Was I naive.
I recently received a missive from ILP saying I had joined a defined contribution scheme in 2007.I do not remember signing anything to do with this. Has my defined benefit pension been changed to a defined contribution scheme, three years after I left the company?Can they do this.?Where can I find information, who were/are the trustees.The scheme numbers on the documentation seem totally different.Where do I begin.
I also have a defined contribution scheme and a retirement bond from other employments.

Contact the with details of your former employer. They should have a record of the scheme itself, and should also be able to advise you if there have been any breaches of relevant Pensions Acts. You don't pay the Pensions Board for their service, as they are a State body.

In general, as you are still a member of the pension scheme (a deferred member) I would have thought that you should have been advised of any material changes to the scheme, including a switch from Defined Benefit to Defined Contribution.