Pay rise in the department for some and not other
I work for company A, who pays my salary through company B something to do with head count. I have worked with this arrangement for 15 years. At the beginning of my contract i was told ( oral contract?) that i would be under the same terms and conditions as the employees of company A. who do the same job. At the time there were 4 company A employees within the department , only 2 are left. By enlarge they have honoured the terms and conditions, eg whenever company A employees have had a pay rise or bonus, It’s reflected in our pay by company B. Essentially company B is paid by company A to cover our salary. This year company A have had a pay rise but not included us. Company B implies that we are now on their terms and conditions. This was apparently discussed and agreed on by the 2 companies last year and contracts agreed, but we were not part of it and only finding out now when we questioned why others had got their pay rise and not us.
Can I challenge this decision?