Talia Pope had phoned the control room five times on the morning of November 11 2017 to try to confirm the arrangements for her niece to speak to an officer about an allegation of receiving indecent images via Facebook.
The teenager, who suffered from severe epilepsy, was reported missing from her home in Swanage later that day.
The 19-year-old had been diagnosed with post-traumatic stress disorder after revealing she had been raped by a man when she was 16 and was worried about his release from prison.
Dorset Coroner’s Court was played the series of calls Ms Pope made to Dorset Police about the meeting.
In the fifth call, the handler speaks to an officer at Wareham police station saying she has Ms Pope on the line about her niece.
The officer replies: “This is the fifth call I’ve had. The last call ended with them talking absolute rubbish.
“I have no idea who they are, what they are on about and they started calling me a drag queen, so I decided at that point to hang up.
“I’ve asked control not to put any more calls through because I think they are taking the piss, to be honest.
“If they are there, put them through and I’ll see if I can get some more sense out of them.”
In an earlier call, a control room handler speaks to an officer at Wareham police station.
While laughing, the call handler says: “She’s calling in regard to her niece Gaia, is that right?”
The officer replies: “Yeah, this is the fourth time I’ve spoken to her today, I have no idea what she’s on about. Put her through and I’ll try and help her.”
The jury heard officers could not find any records of earlier calls because they were searching on the system for “Gaia Hope”.
They did find a report but believed it was to do with the alleged rape the teenager reported in 2015 and said it would be a matter for Weymouth CID.
In a call made shortly after midday, Ms Pope is told by the call handler that an officer would ring her on her mobile phone about the complaint to arrange a meeting at her home or a police station.
Ms Pope told the court that when her niece received the indecent images from a man via Facebook it was a “trigger” for her.
“Her anxiety soared, and she was absolutely obsessed with being actively listened to about the images and making a formal report about them,” she said.
Miss Pope-Sutherland contacted police on November 2 to make a complaint and was due to meet with officers to make a formal statement on the day she disappeared.
The court heard that on November 6, Ms Pope made three calls to Dorset Police to confirm the arrangements for the following day with her niece.
On November 7, Ms Pope made five calls to Dorset Police in the morning to try to confirm what time she would bring her niece to the police station that afternoon.
“I wasn’t going to give up until I had the finer details and knew what was ahead of us because of how important I perceived it to be for Gaia’s mental health and the pressure I could see building up,” she said.
Ms Pope drove to her brother’s house where Miss Pope-Sutherland had been staying and said her niece’s behaviour that morning was “chaotic” and “highly sexualised”.
“She needed help. She had quite a bit of medical help, but we were still back, I am sorry to say, to square one,” she said.
She said she collected her belongings and took the teenager back to her home, as her uncle and mother were due to be away.
After the college student was reported missing, a large search operation was launched in the Swanage area for the teenager, including police, HM Coastguard, the National Police Air Service, Dorset Search and Rescue, and members of the public.
On November 18, her body was found by police search teams in undergrowth between Dancing Ledge and Anvil Point.
The inquest continues.