Ineffective Amway eSpring Filter, Increased TDS Following Replacement

For almost 5 years, I've been using the Amway eSpring water filtration system at home. I change the filter every year. Yesterday, it was time to change the filter again, so I decided to take a TDS meter reading. First, I tested the tap water, which indicated 380 ppm (undrinkable). Then I measured the water flowing from my filtration system with the dirty filter, and it was 370 ppm (undrinkable water). I assumed this was usual because of the filthy filter. After changing the filter and measuring again, it still read 350 ppm. I thought if there was an issue with the TDS meter, but when I tested Abant spring water, it read 38 ppm (1st class spring water). So, due to you, my spouse and children have been drinking water that is nearly identical to tap water for the past five years. Yesterday, I tested the water from the purification system several times, and it always surpassed 300 ppm.