Equity & Trusts problem!

I need help in ascertaining the interests/entitlements of each party in this fact scenario:

A is a singer. A owns a music publishing company, RC, which receives A's music royalties and places them in an interest-bearing account in A's name. A has a recording relationship with company B, which owes A a debt of $100,000. C is an agent/manager/solicitor for A. C has not been paid all year, but A promises to do so soon.

A calls C and gives verbal instructions to:

a)make a gift to her friend S of the $100,000 debt owed by B to A

b)Make a gift to her friend X of all the interest in the interest-bearing account held by RC

To get rid of the debt owed to C, A makes a separate agreement with C to assign $50,000 of the debt owed by B to C as consideration to forgive the debt owed by A to C.

C immediately writes up the agreement (with no mention of the gifts), signs it, and sends it to A, who also signs it. C calls B and tells it about the agreement. However C neglects to tell B about the gift to S, and forgets to tell RC about the gift to X.

A few days after the coffee meeting and after C's activities, A changes her mind and calls C to cancel all the arrangements.