First, buffering and occasional freezing are going to happen with IPTV. If an IPTV seller tells you otherwise, they are not being honest. When buffering or freezing starts, try changing the channel and then changing back. That often resets the channel. If the buffering or freezing persists restart your router and device. Use Ethernet instead of Wi-Fi. Try a VPN if your ISP throttles IPTV traffic.
It never hurts to have a VPN on your device and services can be found for a very reasonable price. Maple IPTV recommends PrivadoVPN.