Even though I had enrolled, employer didn't deduct my salary for 401K.?

With my previous company, I had enrolled in the company's 401K plan. I also had a 401K loan. For some reason, the automatic deduction for payment towards the 401K loan was done, but not for the 401K enrollment. I didn't realize until about 1.25 months before my last day at work and immediately contacted the HR. I had three more pay periods, but still the company was slow in processing it and only my very last paycheck was deducted for 401K. The company said it was upto me to check the paystubs and they can't do anything about it. So, I missed out on paycheck deductions, savings on tax and also the company's matching on the amount as well, and not to mention, potential earnings in the market as well. Can I do anything about it at all now. It's now been 7 months since I left the company.