I have purchased a 3 phase 10 kva DG set. When supplier came to install and commission DG set, he told that your home is of single phase supply. So the commissiong of DG set can not be done. There is loss of $10000 to me. Please advice me , what is way out. How we can use the above DG set in my single phase residence. Pl. reply on priority basis.

How did a 3 phase generator get ordered and installed to serve a single phase system?

As the genset manufacturer stated, you can't.

Applying a single phase load to a 3 phase generator will cause the unit to operate out of balance, so to speak.

A longshot method would be to purchase a single phase load bank that would be connected to the un-used phase. This would get you through commissioning, and it would be needed to stay connected, so there would always be a load on the unused phase.

10kW is pretty small for a 3-phase genset.

I have to ask, who made such a mistake?
There are ways around this, but by far the easiest thing is going to be simply get a new single phase genset. You can always sell the other one if you can't return it.