Ваше мнение противоречит условиям обслуживания Upwork, которые Вы принимаете, начиная работу там. Upwork не является стороной контракта, который Вы заключаете с клиентом. Upwork только помогает Вам найти друг друга и заключить контракт:
If a Client and Freelancer decide to enter into a Service Contract, the Service Contract is a contractual relationship directly between the Client and Freelancer. Client and Freelancer have complete discretion both with regard to whether to enter into a Service Contract with each other and with regard to the terms of any Service Contract. You acknowledge, agree, and understand that Upwork is not a party to any Service Contract, that the formation of a Service Contract between Users will not, under any circumstance, create an employment or other service relationship between Upwork and any User or a partnership or joint venture between Upwork and any User.If a Client and Freelancer decide to enter into a Service Contract, the Service Contract is a contractual relationship directly between the Client and Freelancer. Client and Freelancer have complete discretion both with regard to whether to enter into a Service Contract with each other and with regard to the terms of any Service Contract. You acknowledge, agree, and understand that Upwork is not a party to any Service Contract, that the formation of a Service Contract between Users will not, under any circumstance, create an employment or other service relationship between Upwork and any User or a partnership or joint venture between Upwork and any User.