All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Lying is forbidden and it is one of the great major sins especially in buying and selling as it eradicates the blessing of the sale and it may even lead to consuming people’s money without right. Ibn ‘Umar narrated that the Prophet said: "The buyer and seller have the choice to invalidate their contract as long as they do not depart from each other. If they are truthful and show the deficiency –if any –in the product, then they are blessed in this sale, but if they lied and hid the deficiency then the blessing in their sale is eradicated." [Al-Bukhari and Muslim] Therefore, it is not permissible to lie to the customers and if the company needs to avoid the anger of the customers, then Tawriyah (saying something which has more than one meaning and intending a meaning different from what the listener is likely to understand) may be used instead of pure lies provided that using Tawriyah does not lead to harming others or taking some of their rights.
Hence, you should continue advising the people who are running this company in a soft and gentle manner and show them this present Fatwa if you do not fear harm as Allaah may benefit them with it.
However, it is not permissible for you to continue working in this company if your work requires lying without a necessity, or that lying leads to consuming customers’ money without right. In this case you should look for another job and if you do not find any and you are obliged to continue working in this company, then it becomes permissible for you to continue working in it while avoiding as much as possible to lie until Allaah facilitates for you another job. If you find another job, then you must stop working in this company.
Allaah Knows best.