What to do if the phone interrupts the router?

Question

Iron

hardware: LG e445 (T) phone, Lenovo v580c (H) laptop, TP-Link TL-WR740N (M) wireless router.
The last element was previously distinguished by strange behavior: it turned off devices, gave an unstable signal. After updating the firmware, the old problems disappeared, but a new one appeared, which I can’t explain in any way.
I will describe in stages:
1. (M) is turned on, broadcasts stably, (H) is connected to it.
2. Turn on WiFi on (T). Connection takes about 2 minutes.
3. Stable broadcasting lasts only 30-40 seconds.
4. (T) randomly disconnects, (H) with Win 8.1 writes "Without Internet connection"
5. "LogIn" on (M) stops working adequately, no device can connect.
Result: (T) became a remote broadcast switch (M).
The location (M) relative to other mouths did not change.
What exactly is the problem? Routing errors, hardware defects?

Answer 1

Doesn't lay down, but LAYS! Even the browser underlines the error.

Answer 2

It was similar (albeit a TP-Link TL-WR741ND router, a computer connected via TL-WN727N, and a different phone :) on native firmware (Kyivstar). I decided to switch to OpenWRT.