Sam Dong Process Engineer interview questions

I was contacted by SamDong America through my University's Engineering Career Service with a quick 15 minute phone call. After talking a little bit about my resume they asked for an onsite interview about a week later. Upon arrival, I filled out a hard copy application and background screening application. Next, I was brought into the Lead Engineer's office with the HR manager and was asked a couple simple behavioral questions. They spent most of the interview talking about their rapid growth and how they needed another engineer to help with the work load. Last was a quick tour of the facility. I was told I would be contacted in a couple of days at the latest. After hearing nothing for over a week, I received a call offering me the position. $50K with benefits. I told them that I was interested in moving forward with the hiring process, however, I'd like further explanation of benefits and to potentially negotiate salary. I was sent an email with a brief overview of benefits, ie. no vacation time until after a year, no 401K available until after a year and absolutely no explanation of health packages. I promptly sent my counter offer and expressed my excitement to start my career with them. I never recieved a reply and a couple weeks later, saw the job reposted on my University's Career Service. Looking back, I feel the entire process was unprofessional. It seemed as though the HR department had never encountered a counter offer before, let alone written an offer letter! I wouldn't recommend wasting your time with this company, unless you have other option but to settle.