refusal to do as asked

I handed in my Samsung Tab 4 to have the charging unit replaced after only having the devise for about 6 month. after two weeks I had to call them to get a reference number and find out what was happening with the tablet. I was told that a quote had been sent, (I never received said quote) I asked them to please resend it to me and gave them an alternative mail address it took them three days to mail it to me. The quote was to replace the screen as well as the charging until, ( and yes the screen did have a crack in it) but it still worked. the staff at the repair centre refuse to repair the charging unit stating that they have to repair the screen as well, this is very strange as I have had a previous tab charging unit replaced under warranty when the screen was also cracked, the team leader stated this morning that it had always been the policy if the unit was under warranty. then changed her stance and said it was a new policy this year. All I want is my tablet back with a new charging unit so that I can use it again. this is not the only issue I am having with Samsung at the moment as my wife's S6 is a piece of junk that has given problems and it is only about 4 month old.