Never had a problem with AIS in Isaan. 6 months unlimited internet at 6mbs 1800 baht. I use about 70GB per month and there has been no slow down or drop out. Phone coverage good too.
My experience is that they will not renew if you go below the minimum during the year even though they told me they would if I deposited the right amount for two months. Went back after two months and still no! Cant believe a word they say as they just make it as difficult as possible.
then you have a much more cooperative immigration office. Congratulations. On many occasions I have asked for information on several issues only to be told something different when I comply. I had to visit 8 times before I finaly got the necessary documents to obtain a driving license. Each time something different required and another list.
They will always find a way to prevent you getting your extension. Dont waste your time and just pay an agent. No hassle. No stress. No mountain of copies of all the papers you have ever had and first class service if you pick carefully.