If your telephone is not working the way you think it should, here are a few tips to help isolate the trouble before you send the phone out for repair:
Most problems with phones are caused by bad handset cords, handsets, handset cord detanglers, line cords, or damaged jacks.
1) If you use a handset cord detangler, realize that it will, sooner or later, cause static on the talk path. I recomend not using them.
2) Unplug the "problem" phone from all cords including the handset cord.
3) Take the "problem" phone to a location where you have a perfectly functioning phone of the same model.
4) Unplug all cords from the known "good" phone and plug them into the "problem" phone. Is the trouble gone?
If no, then your phone really does need repair. Call your telephone service company or send the phone into a good telephone repair company. Look for a company that has been around for at least 10 years or so. Also, there are many low cost, fly-by-night repair companies. Use them at your own risk. You get what you pay for.
Always include problem descriptions with any phone that you send out for repair. Problems that occur twice a day when you use your phone may not be readily apparent to a repair technician.
If yes, then replace the handset, handset cord, and line cord one at a time. When the problem comes back, that component is the culprit.
If it turns out that the problem is not caused by the phone, handset, or cords, call your telephone service company to come out and trouble shoot your wiring and system.