Server cannot process requests with body prefixes

Hello,

I created a simple Webservice that works for some requests, but fails for others. Specifically, when the following POST request is sent to the server, it works:

<?xml version='1.0' encoding='UTF-8'?>
<S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
<S:Body>
<acceptCharge xmlns="http://sample.ws.com/">
<request>
<RequestID>12648638354235</RequestID>
<ChargeAmount>$12.98</ChargeAmount>
<ChargeDate>2020-05-01T11:38:19.209Z</ChargeDate>
</request>
</acceptCharge>
</S:Body>
</S:Envelope>

However, when this request the following POST request is sent (note the added text in red) it does not work. A System.NullReferenceException is thrown because the 'request' variable never gets set.

<?xml version='1.0' encoding='UTF-8'?>
<S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
<S:Body>
<ns2:acceptCharge xmlns:ns2="http://sample.ws.com/">
<request>
<RequestID>12648638354235</RequestID>
<ChargeAmount>$12.98</ChargeAmount>
<ChargeDate>2020-05-01T11:38:19.209Z</ChargeDate>
</request>
</ns2:acceptCharge>
</S:Body>
</S:Envelope>

In this case, I do not have control of the Client message structure, so I cannot simply remove the namespace/prefix to get the server to work like I did in the first example. Any thoughts on what is causing this? or how I can remedy it? (ASMX attached below)

namespace TestAPI
{
    /// <summary>
    /// Summary description for WebService1
    /// </summary>
    [WebService(Namespace = "http://sample.ws.com/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.None)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class WebService1 : System.Web.Services.WebService
    {
        [DataContract()]
        public class DataInput
        {
            [DataMember]
            public string RequestID { get; set; }
            [DataMember]
            public string ChargeAmount { get; set; }
            [DataMember]
            public string ChargeDate { get; set; }
        }

        [DataContract]
        public class DataOutput
        {
            [DataMember]
            public string RequestID { get; set; }
            [DataMember]
            public bool UpdateSuccessful { get; set; }
        }

        [SoapDocumentMethod(Action = "http://sample.ws.com/Endpoints/acceptChargeRequest", ResponseElementName = "acceptChargeResponse")]
        [WebMethod(Description = "Operation to respond to Accept Charges")]
        [return: XmlElement(ElementName = "response", Namespace = "")]
        public DataOutput[] acceptCharge(DataInput request)
        {
            System.Diagnostics.Debug.WriteLine(request.ChargeAmount);
            DataOutput[] vRes = new DataOutput[]
            {
                new DataOutput()
                {
                    RequestID = request.RequestID,
                    UpdateSuccessful = true,
                }
            };
            return vRes;
        }
    }
}