Rented Premises

Dear Sir, I have a tenant using our premises for last more than 30 years which was a proprietorship firm running a Pharmaceutical Distribution house. Now they have shifted their main office some other location and still continue being tenant at my place keeping it locked and stocking materials in that place. We don't have any written agreement with them. Now, the premises is formerly owned by my uncle and he expired on 5th August 2016. In his will the whole property has been gifted to me and all the formalities of name transfer is under process. From August onward the tenant is issuing us a cheque in name of my uncle. We have issued a letter and returned them all the 6 cheques to them requesting to issue the cheque in my name as the legal heir is myself. Now, they have issued a letter stating that they need legal documents stating my name as owner. The documents they are asking are: 1. Death Certificate of the actual owner 2. Legal heirs certificate of the actual owner 3. Mutation of the land in my name on which the premises is located 4. Mutation of the Municipal holding of the said shop in my name 5. NOC if any required by the other legal heirs of the deceased person. Also would like to know that are they legally asking for correct documents or we can deny for any of the documents above mentioned to submit to them. One more issue we have encountered in last few days that the day they shifted to the new premises the same firm have been converted to partnership firm and the same has not been informed to us officially. The actual owner is now having just a share of 2% in the firm. So, i would like to know that can we change the case into legal matter or there is no pointing of fighting a case to vacant the premises. My note is that the owner introduced a partner without our knowledge and the shop was given to the firm / owner as an indiviual.