Threading one's eyebrows

Q: I know that the Prophet curses a women who threads her eyebrows. But in Islam, nikah is taken very seriously and Allah hates divorce. Also a wife is supposed to obey her husband. I heard it is ibbadah, obeying your husband. My husband would like me to thread my eyebrows. Now I feel insecure, I feel he will look at other women because I keep refusing and he really wants me to thread. In such cases are we allowed to thread our eyebrows. My marriage is at stake.

Avoiding paying interest

Q: While I was studying at university (in the UK) I regrettably took out a student loan due to my lack of deen at the time, now I have come to realise that this was totally impermissible and wish to make amends.

According to the terms of the loan, I do not need to repay the loan if I earn below £17,775 per annum. The loan will be written off if I do not earn above this threshold after 25 years. I can repay the loan (plus interest) and make taubah but I feel very uncomfortable with this. My other option, which I am fully prepared to undergo, is that I continue to earn below the threshold for the next 25 years. I want to know:

1. Whether it is permissible to deliberately earn less in order to avoid paying any interest?

2. Whether I should repay the loan (through voluntary payments) but not the interest?

3. Whether I should simply repay every thing and just make taubah thereafter?