I had a similar situation – tracking appeared yesterday, changed delivery to today and then this morning it changed again to Monday. Need to travel from London on Monday at midday and I live near Liverpool.
You seem to have spoken to a nicer person on the phone than me- the woman I spoke to at TNT just kept saying it wasn’t even at the Liverpool depot yet, there was nothing she could do and even if I wanted to pick up they needed 24 hours notice and they wouldn’t be able to do that until it arrived at the depot.