Was not to be taken in a network with 2x Vodafone EasyBox 802 in operation

My Vodafone EasyBox 802 with ADSL internet I have connected with CAT5 cable as a switch with a 2 EasyBox 802 and thus operate two independent WLAN networks with a DSL access. In order to get a better wireless reception in the garden, I decided for the TPLINK TL-WA830RE range extender.

Since my LAN and WLAN is protected with MAC filters, I first entered the MAC address of the repeater in both Easy boxes for both LAN as well as WLAN. Then I have the TP-Link connected to a notebook and made through the wizard to connect to a EasyBox. At once I had my tablet from access to the settings of the TP-Link and also came to the Internet. After I then also wanted the Internet from from notebook via WLAN, broke the connection together. Neither from nor from Tablet from notebook I came even to the Internet. Even after the TP-Link was off was anything yet. A reboot of tablet and notebook was unsuccessful. Only a restart of EasyBox brought success in TP-Link off. After switching on the TP-Link was nothing.
I then reset the TP-Link and a manual installation made after I first adapted the IP address of TP-Link my network. The internet worked with the tablet to also wanted the notebook to the Internet.
With a WiFi Analyzer on the tablet then I could find that the TP-Link constantly the wireless channel changed once a second WLAN device was added, with the result that the Internet connection collapsed.
Again reset the TP-Link and all Einstellmöglichekeiten in TP-Link and the EasyBox played out, with / without encryption and with / without MAC filtering both as range extender as well as an access point. Without Success
Frustrated, I wrote an email to the TP-Link Support. Even after 1 1/2 weeks I received no reply.
Then I sent to the TP-Link AMAZON as broken back.

The new device that I give 2 days later was no better. After automatic installation via the WPS buttons when switched off encryption and MAC filtering the Internet access worked well only as long as only one wireless client communicating. 2. As soon as a WLAN client matters worse, was again carried out a channel change and nothing was more. After restarting routers and repeaters, the repeated games. Even a fellow certified network engineer has been bitten on the part of the teeth.
Frustrated, I have the TP-Link sent back to Amazon.

Also useful is the TP-Link only as an access point when it is connected via CAT5 cable to the router.

And by the way. The TP-Link has a very poor transmission power. Even if he is right next to the router is its transmission line despite the externally mounted antenna about 25-30% lower than the transmission power of the Easy boxes.

By the way, even after 4 weeks, the TP-Link Hotline has not reported on my e-mail request,.

I can only say: hands off - never buy.

Addendum:
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Have the MEDION wireless LAN amplifier MD 86977 brought me the MAC address in the MAC filtering on the router deposited, the WPS button on repeaters and wireless router with active MAC filter and everything works right away. So it must be. Just great! Now I have in the garden perfect wireless reception with internet access.