Yes, there is an early termination fee (ETF) if you choose to terminate your contracted mobile plan. You will be charged an ETF of your monthly subscription multiplied by the remaining months in your contract.
For example, X buys a $10 plan on a 12 month contract. After paying 3 bills of $10 each, they choose to terminate the contract. X would need to pay $90 as the ETF. (MRC * Remaining months)