Excel is correct.
You keep bringing down zeros, so you get a repeat of the following:
Bring down a zero
1000-110 = 10 the answer is now 1111.1
Bring down a zero
100 is less than 110 so the anser is 1111.10
Bring down a zero
1000-110=10 so thwe answer is 1111.101
And so on.....
The result is 1111.1010101010101010101010...
By the way, two's complement is a special case of the binary number system. If they just ask you to do a binary division then there is no need to do any of it in twos complement, in fact strictly it is the wrong thing to do. That is, you can just do the subtraction directly in binary.