PLEASE HELP ASAP BRAINLIEST FOR WHOEVER ANSWERS CORRECTLY!!!!!!!!!!!!
(4) However, I did not receive the prepaid envelope with my new phone. (5) I contacted the customer service department twice, once on September 28 and again on October 2 to have them send me a prepaid envelope. (6) As a result, I received two more shipments that contained the same thing: instructions on how to send the defective phone back. (7) However, neither shipment contained the prepaid envelope that I was supposed to receive.

(8) Alas, I called the customer service department again on October 10. (9) The manager who I spoke with told me that the shipping label used by Chit Chat Inc. to ship the new phone included round-trip postage. (10) Although doubtful, I tried to schedule a pickup on the Central Parcel Service site. (11) As I expected, the tracking numbers were invalid. (12) There is no such thing as a round-trip shipping label.
(13) Having failed with the first manager, another manager with whom I spoke ordered the prepaid envelope without hesitation. (14) However, she could not guarantee that the warehouse would actually send it. (15) She added that she had no control over the warehouse. (16) On October 12, I received yet another package with instructions but no prepaid envelope.
Which sentence contains incorrect pronoun usage?
A. sentence 12
B. sentence 9
C. sentence 4
D. sentence 16