Get data using REST API Ringover - POST method

Hi,

My name is Julien, Business Analyst, its been few days that i try to Get data from a REST API - POST method with a query using M.

Here the query :

(StartDate as text)=>
let
    Url = "https://public-api.ringover.com/v2/calls",
    Token = "here is my key",
    EntitiesPerPage = 100,
    StartDate = Date.ToText(Date.FromText(StartDate), "yyyy-MM-ddT00:00:00Z"),

    GetJson = (Url, LastIdReturned) =>
        let Body = "{""intra"":false, ""limit_count"":" & Text.From(EntitiesPerPage) & ",
    ""start_date"":""" & StartDate & """,
    ""last_id_returned"":" & Text.From(LastIdReturned) & "}",
    Options = [Headers=[ #"Authorization" = Token ], Content=Text.ToBinary(Body)],
            RawData = Web.Contents(Url, Options),
            Json = Json.Document(RawData)
        in  Json,

    GetEntityCount = () =>
        let Json = GetJson(Url, 0),
            Count = Json[#"total_call_count"]
        in  Count,

    GetPage = (LastIdReturned) =>
        let Json  = GetJson(Url,LastIdReturned),
            LastIdReturned = try List.Last(Json[#"call_list"])[cdr_id] otherwise 0,
            data = try Json[#"call_list"] otherwise null,
            res = [Data=data, Next=LastIdReturned]
        in  res,

    NbRecords = GetEntityCount(),
    EntityCount = List.Max({ EntitiesPerPage, NbRecords }),
    PageCount   = Number.RoundUp(EntityCount / EntitiesPerPage),
   
     GeneratedList =
        List.Generate(
        ()=>[i=0, res = GetPage(0)],
        each [i]<PageCount and [res][Data]<>null,
        each [i=[i]+1, res = GetPage([res][Next])],
        each [res][Data]),
   
    Table = Table.FromList(GeneratedList, Splitter.SplitByNothing(), null, null, ExtraValues.Error)
in
    Table

It's a bit complicated due to the pagination, and this query does not works and i not find why, actually its return the all lists but duplicates of the first one.

Here is the following link of Ringover for use there API but it does not help me neither : https://developer.ringover.com/

I have ask help from Ringover or colleagues but im still stuck.

If someone can help me, it will be wonderfull...

Thanks a lot

Julien