TYKO - Battery issues

I purchased a brand new TYKO device in April 2019. Eversince the date of purchase, I've had to replace the battery unit 3 times (luckily I kept the receipts, so I was able to claim all the replacements under the warrantee). I ONLY use the original charger cable that was provided & an original TWISP adaptor and ensure that I never overcharge the unit , but still this happens! My last exchange was done 6 days ago, and now - once again the battery is unresponsive.