Can my husbands job make us pay double for insurance if they didn’t sign us up in time?

My husband and I moved states back in September. He started a new job a few days after we moved. My job doesn’t offer insurance, but his does, and we signed up with them a few weeks after he started there. I have a lot of health issues and have to be on prescription medication, otherwise, I’ll have seizures and I struggle with multiple mental illnesses that also require medication. My husband has bad teeth, we both have bad joints, we both have bad vision… the list goes on.

Late last month/early this month, we kept pushing and asking about when our benefits will kick in because I’ve had to make 3 trips to the hospital since we’ve been here, just to get my medication (racking up over a 900 bill each time) and I’ve got to go back for another visit within the next few days just to get another month supply. I pay over $900 for only one medication.

His manager didn’t know anything about it and shrugged it off saying “oh someone’s going to come talk to you when you hit 90 days” or “You’ll need to speak with HR” etc. In 2 days, my husband will be there for 120 days. My husband finally had a chance to explain to this manager how dangerous of a situation it is for me to not have health insurance, seeing as I work from home and am alone all day, and if something happens to me because I’m not able to get my medication then nobody will know until it’s too late. He explained to his boss how much we get billed every time I go, and his manager finally had HR speak to him. The HR lady told my husband he was supposed to get benefits after 30 days, his manager told him it was 90 days, and today he spoke to the corporate HR (he works for a dealership so she’s the highest he can go) and she told him he was supposed to get benefits after 60 days. She informed him that since he was supposed to get benefits since his 60-day mark, in order for us to get insurance, we have to pay double what we originally would be paying until we’re caught up since he “didn’t sign up”, even though it was an error on their part. According to them, we’ll be paying $1,320 a month for 3 months. We don’t make enough to be able to pay for this, along with our bills.

My question is: Since my husband and I did sign up for benefits and it was a fault on the employer’s end, can they make us pay double in order to get insurance?

Edit to add: I am 22, he is 26, he’s employed by a dealership, and we live in Oklahoma.