Mark - I am sorry to hear what you are having to go through. There is no accounting for mothers who block access to the children. I hope that your situation improves soon and that you will be re-united with your son.
The good thing is that he is now 12 (the same age as my grandson) and he has a voice which hopefully will be heard. Also you have been texting each other until recently and your son has clearly said he is missing you. Perhaps his mother has read the texts and feels aggrieved about it!
Don''t give up and keep positive. Remember it is the child''s right to have a meaningful relationship with both parents.
3 days with no contact with my son. She knows how to ''play'' me.
It''s a skill some people have Mark. My ex. dil played my son and us for nearly 12 years. She got all the support and help she needed from us, financially as well as us caring for the children on a daily basis.
That didn''t stop her trying to ensure that none of us had contact with the children. Fortunately she didn''t get her wish.
Sometimes I wonder about Karma, but it seems a long time coming!