Remove invalid Mobile number from a IEnumerable list in MVC

Question

I am trying to remove invalid mobile number from a IEnumerable list when regex don't matched

C# Code

public ActionResult Create(attachmentcsv)
{
    CsvFileDescription csvFileDescription = new CsvFileDescription
    {
        SeparatorChar = ',',
        FirstLineHasColumnNames = true
    };
    CsvContext csvContext = new CsvContext();

    StreamReader streamReader = new 
    StreamReader(model.attachmentcsv.InputStream);
    IEnumerable<MobileRecipient> list = csvContext.Read<MobileRecipient>(streamReader, csvFileDescription);

    foreach (var mobilenumber in list)
    {
        Regex regex = new Regex(@"^(\+44\s?7(\d ?){3}|\(?07(\d ?){3}\)?)\s?(\d ?){3}\s?(\d ?){3}$");
        Match match = regex.Match(mobilenumber.MobileNumber);
        if (!match.Success)
        {
            // I want to remove the number from the list here
        }                            
    }
}