Kia - Diesel Regeneration Filter

I bought Kia Sonet HTX Diesel MT on **th March, ****. Just after driving for nearly *** Kms, I got DPF signal which I was not aware of.
When I went to Kia service centre in Fazal Ganj Kanpur on **th April,****. I asked them about that sign and they taught me a way to resolve and that process uses nearly *-* litres of diesel to fix the issue.
Again at ***kms, it started showing the same DPF issue and I burnt *-* litres of fuel to correct that.
Again at *** kms, it showed me the DPF, I came to Kia service centre in FazalGanj Kanpur, they changed a small part called "sensor" and assured that it wont happen again.
Again, at ***, ****, ****, **** kms, it did the same thing, now I was sure that there is some major engine issue. I immediately called them asked them to take back this car.
They came and picked it up on **th May, ****.
Next day, I called Rajan from Kia, he told me that they observed that DPF happened for ** times during my use of **** Kms of that car and they are consulting with Kia to resolve this.
Next day, they told me they are cleaning a few things to diagnos.
Next day, they said that Kia suggested them to change fuel pump.
Next day, they said that fuel pump is fine but they are still not sure why this is happening and now they are saying that it is under diagnose.
Now, I am sitting on *th day and I don't have any clarity.
Now, I have decided that I want a new car in replacement or a complete refund on my money.