Andrew Taylor, 30, pleaded guilty to harassment and was given an 18-week prison sentence at West Cheshire Magistrates Court in Chester yesterday.
The court heard he had made more than 80 calls to the mobile number of the teenage girl, as well as sending her offensive messages via phone app WhatsApp between February and October last year.
He pestered her, making sexually suggestive remarks.
In his defence Taylor, of Fairford Road, Lache, Chester, said he did not know the girl’s identity and had been playing a game with friends whereby they called random numbers to have “banter”.
However, magistrates told him the offence was serious enough to warrant an immediate custodial sentence due to the age of the victim, the offensive nature of the communication with her and his “persistence”.
Rob Youds, prosecuting, said it was not known how Taylor had acquired the victim’s telephone number, which police telecoms experts discovered was called 82 times from the defendant’s phone.
Reading the victim’s account to the court, Mr Youds said: “He [Taylor] would phone me up and say he would come to see me and stay at mine. I would refuse and he would reply ‘it’s your loss’.”
The content of the messages and calls became more offensive, to which she occasionally retaliated.
“She ends up telling him the police will become involved,” Mr Youds said. “The messages left her feeling scared. She has never given her number out to anyone other than her friends.”
Mark Lever, defending, said Taylor had been out of work last year and was suffering with depression and anxiety.
He said his client would spend days sitting around with his friends, drinking cider and calling mobile telephone numbers at random, which was how he initially made contact with the schoolgirl.
“It's something he regrets doing and something he wants to put behind him,” Mr Lever said. “He has changed considerably since October.
“At that point he was drinking very heavily and abusing class A drugs. He has now managed to stop drinking completely and has not taken any drugs.”
He described Taylor, originally from Ellesmere Port, as an “impressionable young man” who was led astray after falling in with the wrong crowd.
Mr Lever said Taylor had enrolled on a scaffolding course and was now “determined to get his life back into some sort of perspective”.
The court heard Taylor had six convictions spanning eight offences, one of which related to harassment.
Besides his 18-week prison sentence he was also made the subject of a restraining order, preventing him from contacting the teenage girl, and was ordered to pay a victim surcharge of £80.
He was also jailed for 14 days for stealing two bottles of wine from the Co-operative in Ellesmere Port on November 29 and 30, to run concurrently.