Snoopy

Well, it's a little difficult to comment out of context, but I'll give it a try.

1) Is the discount a refund? My impression with the first statement is that the person is asking how they receive the discount in cash terms - for example, if the discount was not originally applied when it should have been how will they receive their £5.30.
2) It sounds like a genuine compliment. The phrase 'deal with' generally means 'to have dealings with' so the person is saying that you have been a good person to work with, and that in their opinion you have given good service/done a good job.

I hope that helps.

1) Yes I agree with Fifth, the person is receiving a 10% discount and is inquiring on how to get the money.

2) "You have been a star to deal with" is apparently a complement, though it's an odd phrasing. To call someone a star I assume carries a positive meaning. Deal as a verb has these meanings:

Main Entry: 2deal
Function: verb
Inflected Form(s): dealt \ˈdelt\ ; deal·ing \ˈdē-liŋ\
Date: before 12th century
transitive verb
1 a: to give as one's portion : apportion <tried to deal justice to all> <dealt out three sandwiches apiece> b: to distribute (playing cards) to players in a game
2: administer , deliver <dealt him a blow>
3 a: sell <deals drugs> b: trade <deal a player to another team>
intransitive verb
1: to distribute the cards in a card game
2: to concern oneself or itself <the book deals with education>
3 a: to engage in bargaining : trade b: to sell or distribute something as a business <deal in insurance>
4 a: to take action with regard to someone or something <deal with an offender> b: to reach or try to reach a state of acceptance or reconcilement <trying to deal with her son's death>

http://www.merriam-webster.com/dictionary/deal[2]

The meaning in the sentence you are asking about is with definitions 3 or 4.

I agree with both of the above. The term 'deal' can be taken as just another way to a person doing business with you. Every new job takes some getting used to and a fear of the people in charge is normal until you get used to the work and your confidence increases. Try to relax and just think of answering one customer at a time and learn from each transaction. It'll get better. Hoping for the best.

Just to add to Virgil's comments, calling someone a 'star' is definitely a compliment. Perhaps it is a peculiarly British phrase, but it's in very common use here and always means something nice

Oh is it common in Britain. I didn't know that. Thanks.

Thanks all of you!!!!
You are all kind-hearted!!