Thermos Double Wall Insulated Teapot Thermocafe Questions & Answers

Please advise stockiest in Australia

I bought this teapot last year and I really liked it. However, the main problem is that it seems that there is a gap right in the bottom of the teapot (in between the double wall) and some tea remnant gets trapped there and you can't get rid of it. You can hear the liquid when the teapot is shaken. When the teapot is washed and put upside down, you could see this dark liquid remnant (from tea) tripling from inside which is not very hygienic. I would be grateful if someone could tell me whether this is a faulty issue (...).