Default Having problem with galaxy s3 sim card?

I have a samsung galaxy s3 after I update the stock rom to 4.3 im facing sim card problem
Sometimes its detect my sim or sometimes its not (it used to happen every 4-3days and have to restart the phone and sim start working)
But now I fave the Problem daily
Its says please insert the sim after restarting phone 3-4times its detect the sim and start working properly
Its happen daily sometimes 2times a day
Its really annoying
I hv reinstalled the stock rom (as I dont wamt to install any custom one)
Even I ask samsung they said we changed the sim jack
But still facing the problem
Any help please

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