Contacts transferred from samsung to redmi via Bluetooth not found in redmi

[Windows Central Question]

I changed phone from samsung to redmi but my contacts were in phone not in Sim so I sent them via Bluetooth to redmi and I saw that the contacts are there in redmi phone but after sometime only 38 contacts were there but actually there were approx.1500 Contacts plz help me plzz those contact have no backup where are they