だけなくねぇ what does it mean?

Question

暇だったから読んでたんだけど、お前　この漫画　7巻だけなくねぇ

I understand the character is saying "I had free time so I was reading, but you, this manga..."

What I don't quite understand is the final nuance.

You only have 7 volumes of this manga? You are only missing volume 7? I'm aware of だけでなく but here there is no で

Answer 1

なくねえ is contracted/colloquial version of なくない used in the question sense and related to the of yours

• What does じゃなくない mean? Is it a positive?

Similarly:

• 7巻だけない = Only Vol. 7 is missing
• 7巻だけなくない? = Only Vol. 7 is missing, isn't it?

So it is more or less 'You are only missing volume 7?'.