NECTAR CARD POINTS MISSING POINTS

LYNSTEG10

Hi I have had points transferred from avios to nectar and sure enough the points were transferred after 10 days without fail. However i went into to various sainsburys stores to use my nectar points off my supermarket shopping and the checkout service machines showed  i had a balance of 257 points worth 2 pounds wheras my phone app shows i have 8000 points worth 38 pounds.I asked sainsburys floor supervisor and checkout assistants who said and i quotenectar is a different entity and has nothing to do with nectar. They couldnt help me.i checked who owned nectar and sainsburys owned it according to wikipedia. I contacted nectar they said if this happens contact us and they will talk to the staff at supermarket staff,however the supermarket staff said they wouldnt talk to them have never heard of this happening,They said nectar had given false info and apologise on theyre behalf. So to summarise one is blaming the other and my app shows i have thousand of points and theyre machin is showing i have the points i had before the avios transfer. Has anybody ever heard of this,AS THE STAFF ALL HAD NEVER HEARD OF IT AND I DONT KNOW WHERE TO TURN TO