Nightmare trying to trade old phone in!

[HUD209]

So I had an email on the 28th of October saying I could trade my old phone in when renewing my contract and they would give me £150 on top of the regular trade in value. So I spent an hour on the phone signing up to a new contract. Received the new phone, all is well. No sign of the return package after two weeks, I phone Three and speak to someone and they tell me there's nothing to worry about and I'll receive the package soon. Now nearly a month later I still haven't received anything. 

I'm currently on the phone again trying to sort this, wasting another hour of my very busy weekend. 

Is there anyone on here that can help? I just want Three to honor the agreement/offer they gave me

[FraserC]

Ah, sorry to hear this. We understand it'll be disappointing. Have you had reassurance that the pre-paid envelope was on its way? Have you had an email detailing the your instructions?

[HUD209]

No, after speaking to Three they told me to phone another company, I think they're called Ingram. I was on hold with them for over 40 minutes today and was told my details were not even forwarded to them from Three in the first place...