I bought a policy that LFG says I was illegible for. They never told me or my employer this. Do I have a case?

Hi! I started purchasing STD insurance through LFG over a year ago because we were planning on getting pregnant. The benefits were described to me over the phone through an external company called Explain My Benefits, so I never received anything in writing, but verbally agreed to purchase the plan over the phone in October of 2015. I had the baby in December of 2016, contacted my employer for procedure to file the claim as well as other pertinent info regarding the insurance policy. After all the paperwork was filed, LFG sent me a letter of denial stating that I did not meet the work requirements of 30 hours a week (I work 19.4 hours as a part time employee). I contacted my employer to ask how I could have purchased a plan I was initially ineligible for and they stated LFG never communicated this to them. LFG then stated that my employer chose this plan for their employees with the 30 hour a week requirement. I also contacted Explain My Benefits an they stated my employer had the control of sending over a list of eligible employees for certain benefits. Again I never received anything in writing about this benefit plan, but did research online for the employer’s benefits package. No where does is state that there is a 30 hour a week work requirement. I researched Lincoln’s website and no where does it state this either. My employer now says that they did everything they could to try and retrieve my funds (now on maternity leave until August my family counted on this money) and LFG agreed to refund my premium (which is a measly $150 compared to $1,500 expected). Do I have a case here? If the employee document online with effective date October1, 2016 for 2016-17 school year does not state there is a work hour requirement and I paid into this plan, am I owed the funds? Who is at fault? Obviously I don’t want to attack my employer (for fear of getting fired/contract terminated) but I feel the money should be paid to me.