This is a generic way of fetching more than 1000 rows from a search in NetSuite.

more_than_1k.js

console.clear();

var res;

var rows = new Array();

res = nlapiSearchRecord("customrecord_tel_tarifas_globales", null, null, null);

if(res) {
    rows = rows.concat(res);
    while(res.length == 1000) {
        var lastId=res[999].getId();
        res = nlapiSearchRecord(
            "customrecord_tel_tarifas_globales", 
            null, 
            [
                new nlobjSearchFilter("internalIdNumber", null, "greaterThan", lastId),
            ], 
            null
        );
        if(res) {
            rows = rows.concat(res);
        }
    }
}

console.dir(rows);