我姓李却不在你心里

'Wo Xing Li Que Bu Zai Ni Xin Li' translates into 'my surname is Li, but I am not in your heart'. The speaker is emphasizing that despite their existence or efforts to establish a bond with the person, that person hasn't reciprocated their feelings or even bothered to keep track or remember. Here, the surname is less relevant than using personal attributes or information to show being forgotten, disregarded or insignificant to another person.