If the trustees and executors of my mother's estate are refusing to speak to me and I'm a beneficiary, how can I request to have them removed?

Since you mention that there is an executor of your mother's estate, I assume that she left a will.  The will is a public record on file in the probate court that has jurisdiction of the county in which your mother lived.  And if the trust was established under your mother's will, then the terms of the trust are also a public record since they would be contained in the will.  Thus, you should go to the probate court and review these and other documents that are in the probate file for your mother's estate.  Get a copy of the relevant documents and have them reviewed by a lawyer who has expertise in probate law.  The executor and trustee are not required to speak to you, but they certainly are required to carry out their obligations under the will and trust, and to treat the beneficiaries fairly and pursuant to those documents and the legal requirement of fiduciary duty.  This imposes on them a high standard of honor and fairness and an obligation to treat the beneficiaries in good faith.  Once you determine what specifically you are entitled to receive pursuant to the will and trust, a qualified lawyer can assist you in enforcing your rights.