I am considering changing my mobile data plan and am seeking recommendations. Currently, I am using a UnionPay card from a telecom carrier, which has a monthly consumption of over 40GB. I want to know if it is reliable to consider a switch to a new carrier and what the recommended data plan would be for me. I do not use a lot of data and 30GB per month should be sufficient. Additionally, I would like to know if the promotions I see online claiming to offer long-term effective plans with automatic renewal are genuine or not. Thank you for your help!