Last week, Frank left Tel out of his Tottenham squad for the league phase of the Champions League in what was a tough choice, as he faced having too few homegrown squad members and too many who have come from elsewhere.
Tel is yet to start a game for Tottenham in competitive action this season, and after the signing of Xavi Simons, his position is in jeopardy.
He spoke to the media while on France U21 international duty about how the phone call with Frank hurt him as he contemplates his future.
"Quite simply, with respect. He called me, he simply told me his choice, and then you could see the list appear on the networks," said the attacker, as quoted by Le Telegramme.
"It's clear that when you're not on a list, it definitely hurts, but I'm someone who stays pretty positive, no matter the situation, because I think I've worked a lot on the mental aspect, so today it's definitely a disappointment. I would have liked to be there.
"But the coach's choice is the coach's choice, we can only respect it and we're going to work to come back in the best possible way."
The Frenchman has struggled to fully settle in North London since making his switch, and this latest snub serves as another setback for the 20-year-old forward who needs to find his footing under Frank.