I would like to connect to bitvavo via API.

I lack the skills to create the rest clients and web sockets, who would like to assist me with this (for a fee)?
This example is a Restclient, i’d like to achief this with Websocket listener.

(Language = vba.net )

Public Async Function GetBitVavoPortefuille() As Task

    Try

        Dim TimeStamp As String = CLng((DateTime.UtcNow - #1970/01/01#).TotalMilliseconds).ToString
        Dim TotalParam As String = TimeStamp & "GET/v2/balance"
        Dim HashKey As String = HashString(TotalParam, BitvavoApiSecret)
        Dim APIUrl As String = "https://api.bitvavo.com/v2/balance" + TotalParam + "&signature=" + HashKey
        Dim Request As System.Net.HttpWebRequest = DirectCast(System.Net.HttpWebRequest.Create(APIUrl), System.Net.HttpWebRequest)
        Request.Headers.Add(BitvavoApiKey)


        Dim Response As System.Net.HttpWebResponse = DirectCast(Request.GetResponse(), System.Net.HttpWebResponse)
        Dim Read = New System.IO.StreamReader(Response.GetResponseStream).ReadToEnd

    Catch ex As Exception
        Stop
    End Try


End Function


Public Function HashString(ByVal StringToHash As String, ByVal HachKey As String) As String
    Dim myEncoder As New System.Text.UTF8Encoding
    Dim Key() As Byte = myEncoder.GetBytes(HachKey)
    Dim Text() As Byte = myEncoder.GetBytes(StringToHash)
    Dim myHMACSHA256 As New System.Security.Cryptography.HMACSHA256(Key)
    Dim HashCode As Byte() = myHMACSHA256.ComputeHash(Text)
    Dim hash As String = Replace(BitConverter.ToString(HashCode), "-", "")
    Return hash.ToLower
End Function



call to GetBitVavoPortefuille() end up in an error, probably incorrect header and total param ? 

see documentation : https://docs.bitvavo.com/'

Please help