"疎遠になる" and "連絡を取っていない" are used in situations in which you have intentionally/unintentionally lost contact with someone.
You can say "連絡が(来)ない","音信不通", or "音沙汰なし" when someone hasn't reached out to you recently regardless of whether you have been waiting on them or not. "音信不通" and "音沙汰なし" often indicate that they haven't contacted you for a longer period of time, compared to "連絡が(来)ない".
You can say "連絡がつかない" or "連絡が取れない" when you can't reach someone.
Meg and Amy are looking at some collage photos.
- Meg: This picture brings back memories. Actually, it reminds me of my ex!
(この写真)懐かしいな。元カレを思い出すな。 - Amy: Weren't you two together for a while?
別れたんだっけ？ - Meg: No, it was a short term thing. We had this big argument and later on we never linked up. I hate him.
うん。短かったよ。大喧嘩して、それっきり連絡(を)取っていない(or疎遠になっているor疎遠だ)。(相性が)合わない。
Ken is talking to Leo about a girl that he met on a dating app.
- Ken: Oh my God, will I ever find someone that suits me ?!
あーぁ、俺に合う人いない？ - Leo: Wow Ken, loosen up. Aren't you dating someone?
ケン、落ち着けって。誰かと付き合っていなかった？ - Ken: No way, she hasn't been texting me at all.
いや。彼女から全く連絡が(来)ない。 - Leo: You mean she ghosted you...
音信不通(or音沙汰なし)って事か... - Ken: Well, something like that.
まあね、そんなところ。
Ken is meeting up with his college friends after a while.
- Ken: Hey Jim, long time no see. How have you been?
やぁ、ジム、久しぶり。元気？ - Jim: I'm good. Thank you. You look good too. Why aren't Leo and Tom here yet ?
うん。ケンも元気そうだね。レオとトムはまだ来ていないの？ - Ken: Well I thought Leo would've been here by now. I texted him a while ago, but I can't get a hold of him.
あー、レオは来るはず。ちょっと前に連絡したんだけど、連絡がつない。 - Jim: I see. What about Tom? I know that he's usually late, that's one of the reasons why I actually haven't been seeing much of him lately. His behavior gets on my nerves sometimes.
そっか。トムは？まぁ、いつも遅れるから、最近連絡を取っていないんだ(or疎遠になっているんだor疎遠だ)けどね。頭にくるからね。 - Tom: Man, I feel you, actually, he just called me. He'll probably turn up soon.
分かるよ。さっき連絡が来て、もうすぐ来るって。