u/s 146 of companies act 1956 A company shall, as from the day on which it begins to carry on business, or as from the 1[ thirtieth] day after the date of its incorporation, whichever is earlier, have a registered office to which all communications and notices may be addressed.
so in your case the plaint is rightly served in your registered office at ambejogai. there is no such thing as corporate office under companies act 1956.
since all transaction took place in nagpur then the transaction in question will come under the jurisdiction of nagpur high court. as depicted in the case state bank of india vs. sanjiv malik, the mortgage transaction took place at gurgaon but the plaintiff sued the defendant in delhi high court. it was decided that delhi high court has no jurisdiction of this transaction. the transaction comes under the jurisdiction of gurgaon court.
read the entire case here: