Vastu Vihar — Regarding change of flat no after agreement

Address:

Gayatri bhawan, tari mohalla ara, bihar

My flat no 306 is in vastuvihar phase 8/aditi project patna. But it is unfortunate to tell you that my flat no is change to flat no- 304 as pet record. I want to know how it is possible without my concurrence. Pls tell the reason and amend your record.