don't go by police advise, indians know their reputation
They want you to file cases/FIR so that the case becomes complicated and then it becomes a candidate for them to extort money from parties (whether right or wrong)
here is the analysis of the situation
a) Whatever reason between you two, your husband has deserted you and are not very civil about it. You are bound to be hurt, but if you think why the husband/families take such harsh measures (like MIL asking to send your belongings to you and disowning their son verbally) is to protect themselves legally (as laws are heavily skewed in favour of females) - probably this fact may lessen your anger towards their action. These action are not directed against you but to protect themselves
b) You have the following options
i) Don't do anything, continue your life and wait for the other party to take the next action. Pray for miracle that the other party realize their mistake and attempt at reconcillation [morally correct decision as well as legally]
ii) File RCR petition telling the court/husband about your intention to continue the matrimonial relationship. If no positive result achieved by this, at least it will help you in Point iii)
iii) File a divorce case on basis of desertion, claim maintenance and alimony [ again morally and legally right approach]. Here woman gets short changed as they can not always prove husband assets or income and may not get the right maintenance or alimony. I guess Indian laws need to amended to address this problem as women's should not be wronged here. hence few women file false cases
iv) file false cases against ur husbands and their family, get them arrested run in court (morally wrong step, will land up in mess, have lot of mental tension and no chance of getting back with husband