LTE LINE AS SLOW AS HELL

took out a 100gb LTE contact last year just before the end of December 2017 when i connected had fast speeds until the 1 of January 2018 the speed when from 10mps to 0.89mbps how is this possible same sim same position called the help desk they told me they will send some one out but to date noone and no feed back all staff at telkom dont no there left arm to there right and dont no how to fix a problem can telkom phone me so i can return this router and terminate my contract as this product dont work at speeds that is promised from telkom as a customer under the consumers protection act i am giving notice to telkom of my LTE line and ask to cancel my contract ASAP.