Asus — I want my original Motherboard MODEL(M4A78LT-M LE) which was replaced without telling me

Address: Lucknow, Uttar Pradesh

I went to the ASUS SERVICE CENTER(Tezz Kumar Plaza, Hazratganj, LUCKNOW) to show my Motherboard's RAM slots(MODEL:M4A78LT-M LE, SERIAL NO:ACMOAC115527).It stayed there about one month under repairing at last declared dead.Between that time I attempted many calls to the service center to know about my motherboard's repairing condition.In the last call I had there, they just told me that your motherboard is ready & you may take it back now!When I reached the service center they showed me a new motherboard of a different model(MODEL:M4N68T-M LE V2, SERIAL NO:B9M0CS377687), there I claimed to get back my Original MODEL(which was far better then the newer Model, It has an in build AMD 760G GRAPHIC CHIPSET), they told me that M4A78LT-M LE is not available in stock & suggested me to keep that new model for about 3 or 4 months with an extended warranty of 1 year & may get back my original model when it will be available in stock.Also, I demanded a written statement about this further, they convinced me by saying that, "Your data is present in the computer and whoever will be there? will assist you for sure."I have used this Motherboard(M4N68T-M LE V2) about 7 months, while using this motherboard many problems came to me like many games are not running(major drawback) and a few are running but very slow, video performance is really poor, sometimes a blue screen comes up while playing games and the PC get restarted. It's still under warranty.So, I revisited the service center after 7 months(due to some problems) and told my query and all that happened before(the lady employee whom I had met before has resigned) & The new employee is now saying that "It is not possible to get my original motherboard back"and the whole statement was changed as said by the last employee and the system is looking like a...fraud!!! So, I want the Higher Authority to take some immediate action to resolve this issue as soon as possible and help me to get my original model(M4A78LT-M LE) back.