someone claimed my dependent

i’m sure it was my ex boyfriend but he did not see or have my child in 3 years. i efiled and was rejected so I’m mailing tomorrow morning. Even while the irs is investigating, will i still get my refund in the mean time? or do i have to wait until they prove i’m the one who rightfully claimed my child? i don’t want to have to wait months when he probably already got his taxes illegally claiming our child. basically will i still be mailed my check in 6-8 weeks or do i have to wait for them to determine the results?