Poppy Carter, 29, of Upper Lattimore Road in St Albans was found guilty of stalking Carly Bradbury.
St Albans Crown Court heard she poured paint and a corrosive liquid over her work van and sent anonymous cards depicting a cat watching a goldfish.
Passing sentence on Friday, Recorder Leslie Cuthbert called her actions "despicable, evil and vindictive."
He said she had displayed no remorse during her trial for what she did to Carly.
It was just one incident as she targeted Miss Bradbury over a seven month period in 2016.
Carter was also given a six-month night time curfew, a restraining order and told to carry out 84 hours of unpaid work.
During the trial in July the jury heard the stalking happened over seven months in 2016.
Carter employed a private investigator to find out where her ex-boyfriend, Alex Roberts, had moved to with Miss Bradbury.
The following month a dead mouse arrived "belly up" in a Jiffy bag at the home in Watford.
Prosecutor Daniel Wright said her actions had "amounted to the stalking of Miss Bradbury, causing her alarm" and the mouse was an "extremely distressing and frightening thing to find".
Mr Roberts told the jury the incidents left Miss Bradbury "in bits" and she was prescribed anti-depressants.
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