According to the guides here and there Someone reported you which kicks off Bungie investigation to your account and found you guilty with an unstable connection. First restriction is 2 weeks and next time it's 2 month. No one will reply you from Bungie support as their policy mentions that they do not help or discuss or even explain to you what happened. If your connection is perfect in each other game and you still want the explanation Matchmaking is the major issue . They’ve prioritized matchmaking you with players of similar glory yet it generally doesn’t account for where those players are located resulting in unfair latency advantages due to the peer to peer network model you will encounter this issue also if you keep teaming up with players from LFG who are geographically away from you you might be the furthest connection from the other players and your latency to the rest will be high and you end up being detected as an unstable connection.

You are unfortunately one of the many who will not receive feedback as Bungie quite simply do not care for its player base, you will have the few persons parroting help posts to "try assist" and if a moderator or Bungie representative decides to reply, they will most likely will do the same nonsense by referring you to their help guides on how to fix the issue, which I have been through extensively and there is nothing of value that will resolve the issue. Honest opinion, stay away from Competitive, it clearly seems to be the cause. As myself had never had a issue and as soon as I started playing competitive, I also received restriction for network issues that magically appeared according to Bungie. Enjoy the two week break...

Here is bungie's statement regarding the increase in restrictions [quote]Beginning soon, players with the most unreliable connections will receive an in-game warning. We know that connection quality is fluid, so don’t worry if you have occasional, temporary issues. If you receive one of these warnings, please visit the [url=https://www.bungie.net/en/Support/Troubleshoot?oid=12915]Network Troubleshooting Guide[/url]. If your connection does not improve, there are additional guides available that can help you in [url=https://us.battle.net/support/en/article/7871]diagnosing advanced network issues[/url]. If all else fails, contact your ISP for assistance. If your connection does not improve after an in-game warning, and we continue detecting a negative impact on other Guardians, restrictions from PvP activities may be applied to your account. If a restriction is applied to your account, you will be unable to participate in PvP for two weeks. If you continue to play on an unreliable connection that harms the experience of other players, that restriction may be extended.[/quote] ([url=https://www.bungie.net/en/Explore/Detail/News/47555]source[/url]) If for some reason you are not able to improve the stability of your connection, it is recommended to refrain from playing pvp activities as the negative side effects of your connection will lead to longer restrictions. [b]Bungie does not discuss restrictions or bans.[/b]

Get your IP to check your line and also run some home router tests. And if you’re connected via WiFi then I can almost guarantee it’s because of that if your line is fine.