Application of offers to account

[RobS-UK]

Morning,

Last week I agreed a new contract and offers to be applied to my account with an agent via chat. Most of the offers were visible immediately via my billing, but for one the agent said it might take a little longer. 

I got an email a few hours later saying the offer had been applied, but it's for a different amount than I agreed via the chat. 

Noting that I already had to wait for this to be applied, does anyone have experience of this sort of thing from Sky - is it likely I just need to wait a bit longer for them to sort it out or does it seem like a mistake has been made and I need to contact them to chase the offer?

[PandJ2020]

I was told upto 72 hours.  I'd start chasing them as it's not unheard of for offers not to have been applied correctly.