Wedding vendor trying to charge more money than agreed

Hello all,
In a bit of a pickle at the moment: I’m getting married in Italy but have done my invites here in the UK as I thought the process would be a lot easier.
I had found a vendor, contacted her and got a quote.She quoted me £4.95 per invite and that includes (and I quote directly from her message) envelopes, gold foil and bespoke design (enphasis on bespoke design).Great.Sent her a £100 deposit and we started the process. She refused to meet up or have any other calls besides the introductory call before even getting a quote so everything had to be done via email.Now, mine is a proper italian wedding so a lot of things needed a lot of amending which led to a lot of back and forth.Now I am about to collect the final product and she is charging me extra for (again, I quote) “quite a few more proofs back an forth with changes and amendments and reflects more time spent on these”.Now, bare in mind all the proofs were PDFs, she never actually printed anything that ended up not being right that could have led to her losing money.At no point in the process she mentioned she might have needed to increase the price due to the work that was being done. Am I right in thinking that she can’t do this? Or am I being blinded by the sheer cost of this wedding and I’m fussing over something I should get used to?