how to know whether the receipt number on our name or not

Employer had shared me the receipt number and told that in the lottery it was not picked. Employer was not sharing any details with me he had shared just the receipt number , when i am tracking in USCIS portal it is showing that the “application receipt number entered is invalid. please check your receipt number and try again.”

And employer is saying that he opted for Premium , how can I come to know that whether the receipt number employer shared is correct or not, whether the petition was filed against us or employer had shared others receipt number. Please suggest they had charged me a lot of money and they were not giving response. Is there any way that we can proceed legally please guys help me with your inputs.

And one thing employer is not sharing any details regarding the petition.