Do you have the picture to share here for comparison? You should basically get what you ask for, within reason.
I have highlights, and went for a modest money piece (as in, not too chunky) It only costs me £65 for highlights and roots (that's without a cut, when I have it cut, it adds another £35) I'm happy with it, as its what I imagined / asked for.
Sorry I haven't brushed my hair as I'm feeling a bit poorly tonight, but for reference, this is mine to show the noticeable difference between the two colours.
I don't have a fringe, mind. I do think that's the thing that complicates matters. They were right what they said about it looking 'blocky' if they put too many foils in your fringe.
Also, did they use a ballayage board? When my hairdresser uses this, it costs more, takes more time, and looks more 'blended' (my DD gets this)
I feel happy with highlights, as it still looks quite blended for my liking. I used to have 'salt and pepper' hair as a young girl, and that's what I was trying to replicate.