Multi POST query (session mode)

I am trying to interrogate this site to get the list of offers. The problem is that we need to fill 2 forms (2 POST queries) before receiving the final result.

This what I have done so far:

First I am sending the first POST after setting the cookies:

library(httr)
set_cookies(.cookies = c(a = "1", b = "2"))
first_url <- "https://compare.switchon.vic.gov.au/submit"
body <- list(energy_category="electricity",
             location="home",
             "location-home"="shift",
             "retailer-company"="",
             postcode="3000",
             distributor=7,
             zone=1,
             energy_concession=0,
             "file-provider"="",
             solar=0,
             solar_feedin_tariff="",
             disclaimer_chkbox="disclaimer_selected")
qr<- POST(first_url,
          encode="form",
          body=body)

Then trying to retrieve the offers using the second post query:

gov_url <- "https://compare.switchon.vic.gov.au/energy_questionnaire/submit"
qr1<- POST(gov_url,
          encode="form",
          body=list(`person-count`=1,
                    `room-count`=1,
                    `refrigerator-count`=1,
                    `gas-type`=4,
                    `pool-heating`=0,
                    spaceheating="none",
                    spacecooling="none",
                    `cloth-dryer`=0,
                    waterheating="other"),
          set_cookies(a = 1, b = 2))
)
library(XML)
dc <- htmlParse(qr1)

But unfortunately I get a message indicating the end of session. Many thanks for any help to resolve this.

update add cookies:

I added the cookies and the intermediate GET, but I still don't have any of the results.

library(httr)
first_url <- "https://compare.switchon.vic.gov.au/submit"
body <- list(energy_category="electricity",
             location="home",
             "location-home"="shift",
             "retailer-company"="",
             postcode=3000,
             distributor=7,
             zone=1,
             energy_concession=0,
             "file-provider"="",
             solar=0,
             solar_feedin_tariff="",
             disclaimer_chkbox="disclaimer_selected")
qr<- POST(first_url,
          encode="form",
          body=body,
          config=set_cookies(a = 1, b = 2))

xx <- GET("https://compare.switchon.vic.gov.au/energy_questionnaire",config=set_cookies(a = 1, b = 2))

gov_url <- "https://compare.switchon.vic.gov.au/energy_questionnaire/submit"
qr1<- POST(gov_url,
           encode="form",
           body=list(
             `person-count`=1,
             `room-count`=1,
             `refrigerator-count`=1,
             `gas-type`=4,
             `pool-heating`=0,
             spaceheating="none",
             spacecooling="none",
             `cloth-dryer`=0,
             waterheating="other"),
           config=set_cookies(a = 1, b = 2))

library(XML)
dc <- htmlParse(qr1)