Federal Contractor-Health & Wellness Benefit

Hello, I'm a Federal Contractor. I started out 5 years ago with a company, then their contract ended and was not eligible for renewal. A different company took over and it's been a nightmare! Is anyone familiar with the Health and Wellness Benefits? My original contractor would add the excess Health and Wellness benefit to my paycheck which was great. The new company did that also, until we were eligible for the 401 (K). They auto enrolled me into a 401 (K) without notifying me. Didn't provide me any information about the plan, its options or an enrollment form. They started taking my excess Health & Wellness benefit and putting it into my 401 (K). They tell me I can't opt out and that's what their "contract" states will happen. I'm losing almost $400 a month now. It's such a struggle. I know I'm not "entitled" to the money, but it's still frustrating. Has anyone dealt with this?! Any recommendations?