I lengthen my hair to be gathered to a ponytail when the time comes.

I started that process about 3 months ago from starting point, that is, after totally shaving my head.

My problem

My problem is that I went to a barber that did for me the following crappy job:

I have asked the barber to only shave my hair in the crescent around each ear in which my hair is somewhat more curly for some reason and in the lowest part of hair of the nape, where my hair is also somewhat more curly for some reason. I recall I also pointed on the areas "exactly" (quote marks because this is interpretable, of course).

Instead, the barber trimmed some of the hair covering my ear also, thus somewhat (~25%) destroying the balance I had for 3 months and thus lengthening the process from about 6 months to 7 months approximately.

Interim notes

1) I live in the country in which I met this barber as an expat and me and him didn't speak the same mother tongue, but a similar problem happened to me in my far past with other barbers which did share my mother tongue, yet didn't understand that by "around the ear" and "in the end of the nape" (or similar terms and with pointing directly) I meant only to the curly lines and not to the regular head hair that covers them.

2) Interestingly enough, another barber in front of that barber did understand me but she already closed the shop when I went to that barber.

My question

How to cover hair for a barber to prevent cutting that particular hair?

That is to ask;
What kind of flexible (rubber stripe) or hat or whatever I could use to "mecanically" cover the main parts of the hair (such as hair covering the ear or covering the lowest part of hair of the nape) so it would be clear, even without lingual explanations, that I want only the aforementioned curly parts to be trimmed?

_{Yes, I know "some barbers are better than others" but I need an "hacky" way to prevent this problem that happened to me too many times already.}