I have received plenty of emails complaining "cannot enrol into ...", "can you help me?". The answer is "no": instructors are not involved in the enrolment. You need to talk to your College or Faculty Registrar. Also try Undergraduate Administrator of Math Department.
Some Tutorial sections take place in the rooms, which have extra seats (in comparison with the declared maximal size of the section). However some Tutorial sections don't have extra seats. (*)
Some students ask "Can you be enrolled into one section and attend another?" I cannot answer without knowing exactly which sections you are talking about. However it is possible as an exception to a very limited number of students because of (*).
Inevitably, some students (hopefully not many) decide to drop the course. In this case, please, drop from both Lecture and Tutorial sections. First, it will help other students, those who cannot get into desired section. Second, it will help instructors and TAs: we need to know, how many copies of the quiz papers should we make for a particular tutorial section (they will be different). Finally, stopping to attend the course without official dropping the Lecture section brings the financial and academic penalty. Probably, it is not the so for the Tutorial section, but do you want to take the risk?
