Unacceptable clauses in the agreement from the builder

Hi Esteemed Lawyers, I have recently invested in a commercial property in a reputed builder promoted Shopping Mall. I have made around 20% payment till date and now I have received the allotement agreement in which I have very serious objections to some clauses. Kindly assist with the following queries: 1) The builder has mentioned several unacceptable clauses including a clause "any modification in the agreement will make it null and void". Does that mean we can't raise objection to unacceptable clauses? 2) Many of the clauses are clearly dominant and one sided to the extent of being extremely unfair to the consumer. For example- "The builder reserves the right to give the property on lease and the allotee can't object on the term/rent/profit of the same lease". A letter is also attached for the allotee to sign. This clause makes the whole purpose of this investment redundant. Can I refuse to accept any clause? 3) All the charges payable to the builder are on the super built up area whereas in a clause related to point 2 above- "allotee shall be paid a rent only on the actual carpet area" There are many other clauses which are clearly objectionable and one-sided. Please suggest how can I address this and get it amended considering I dont intend to exit from this investment. Awaiting guidance on the above points to help me get clarity on this issue and to take it further. I may also be interested in engaging a lawyer in that city to assist me. Thanks. Regards Narendra Singh