Interest and Gambling

Cash prize draw

Q: To encourage consumers to complete an online customer survey can I offer them entry into a cash prize draw. 5 lucky respondents will get R1000 each for example. Is this permissible?

Medical insurance

Q: I had a question about a friend who sells his medication called Hydrocodone pain killer. He gets it for free under his insurance and sells it to relatives and friends to be used for pain killer? What's the ruling on that? 

Linking one's bank account with someone else's account

Q: Is it permissible for me to link my bank account with my father's bank account at the same bank which contains interest but I am not withdrawing any money neither am I depositing money from his account but just linking it? My account is interest free and the money in my account is not being shared with his money but the "link" is still there.  Is this permissible?

Cash prize draw as an incentive to complete a survey

Q: To encourage consumers to fill out a survey, we offered entry into a cash prize draw as an incentive if you complete the survey. 5 respondents will each win a certain amount of money. After capturing the respondents details, my systems crashed and I lost all the data, I tried everything I could and there is no way of retrieving that data. What do I do ? I have no way of knowing who completed the survey, so how do I choose five winners. Is this form of incentive permissible?