App, Store Service an Customer Service online terrible

So I joined Xfinity last year with a promotional plan that was 64 bucks. Someone at Xfinity made a change to my account I didn’t authorize and I lost my promotional price plan. They stated to me they couldn’t give me my plan back even though I didn’t request the change. Now I’m paying more for Xfinity mistake. I have tirelessly visited the store only to hear they can’t change my payment date just like online customer service. I made a change to payment date back to what it originally was to the 21st since they made it the first, two months ago I made the change and now I was told the app glitches the store can only see the next pay date and it’s wrong an online customer service couldn’t tell me why it hasn’t changed to the new payment date I chose. Overall the store and online customer service is very poor and unhelpful. They couldn’t even prove to me that I authorized the change in service. An it needs to be fixed. You need to have a corporate number on the website cause nothing gets done in store online or in the App that never works correctly.