Call the cable company.
If you are sure it isn't your wiring, then it is likely on them. I had similar issues (as I'm sure others have) where cable has started acting weird. I told them that my high speed internet was dropping at random times for no obvious reason.
The guy came in and started talking about internal wiring, but then I explained to him that it had been working perfectly for months and I had made no changes to my system.
He still switched out all my crimp on F connectors with compression type.
Great.
When that did nothing, he actually tested the incoming signal to find out...
...TO MUCH SIGNAL!
Yes, my house was actually being over-driven which was causing the gear to have issues and the cable company needed to dial things back from their distribution point (a few houses away).
Charge to me? Zero
So, if you are 90%+ sure it isn't your fault and the issues just 'cropped' up then give the cable company a call. They should have the gear and testing equipment to make sure that things get corrected. If it isn't internal to your home, it is not going to cost you a penny.