Can offer letter and appointment letter be treated as same?

Dear Sir, I had joined a company as senior developer 3 months back. On joining I had signed the offer letter that was previously send to me via email. While joining I found the company in ground floor of a residential building. There were no sign boards too. I didn't got any appointment or joining letter even after verbally requesting. After many verbal request we were provided the same copy of offer letter. The offer letter contained clauses that I will be on probation for 3 months. I have to provide 2 month notice period while resignation. Not doing so I will be liable to pay 2 months salary and 1month salary as expanses on my training, knowledge transfer and other expanses. Also I have to pay for the legal expanses. After joining I found the company with lot of problems and saw misbehavior of employer with some employee. After sometime I faced the same misbehavior like scolding for switching off AC. Forcefully returning to office even after office hour that too not for my part of work. Also there was no training or knowledge transfer. And I was asked to work on multiple running projects without any knowledge transfer of any project. There was no process management and not knowing what to do when. Also I found there are no salary slips provided to the employees. I was not assure of legibility of the company. In the meantime time I got an opportunity in a much better company and I left the company by providing a resignation letter and resigned the same day. I had served the company for 1 month 15 days and received salary for 1 month. After few days I got mail from employee that I need to pay 50K for compensation. Then after 15 days I received another mail that I need to pay 65K for compensation. I didn't replied to the emails. Now after 2 months I have received an notice from an advocate asking for 1 lakh for compensation within 2 weeks. In the notice somewhere they mentioned "the appointment letter was issued", in some places they mentioned "the appointment / offer letter" and in some places "you noticee have accepted the appointment letter". The letter I had signed contained "we are pleased to offer you an appointment", and"If you are agreeable to our offer of employment". And this same letter was mailed to me as offer letter. I cannot understand if the same letter be treated as offer and appointment letter. I have consulted a lawyer. After seeing all papers and documents he just told me not to worry a bit and asked me to pay him a lot more and he will send a reply to the notice. I was not getting confidence as he was reluctant to tell me the things I was asking even though I gave consultancy fee. I asked for some time as I am very low on money due to relocations recently. Also my home, the company and my present company are in 3 different states. Can anyone suggest me what will be the right thing for me to do. Can the same offer letter be treated as appointment letter? Thank You