When you're being double teamed or face guarded...screens and cuts are your best options.
Your coach needs to recognize this and have your teammates set screens for you to get open.
You need to also work on good fakes and cuts to get open for the basketball. This is often difficult with two players guarding you; however, it's something you have to get good at if you want the basketball.
Lastly, it's important for you to realize that when you are being double teamed, your team has a 4 vs. 3 advantage. So, by being double teamed - you are in essence giving your team an advantage.