Is there anyone in Atlanta, Ga dematting pets for free?

Hi, I’m reaching out for support. I have a severely matted dog named Denim who is three years old. My family and I have had him since he was about two and a half months old, and we love him dearly. Before getting Denim, we didn’t fully understand the level of upkeep he requires. We’ve also gone through several hardships during this time, including homelessness, which has made it difficult to keep up with his grooming needs. Denim has never been groomed by a professional only by my mom. I’ve tried to help as well, but I’m afraid of hurting him since I don’t have experience. I’m also uncomfortable with my mom grooming him because she isn’t a professional. We’ve attempted to get Denim groomed three times, but each time we were turned away either because his vaccinations weren’t up to date (he does have his shots now, though they may not be current), or because his matting is too severe and too close to the skin. I try to groom him occasionally because I hate seeing him uncomfortable and in pain, but he won’t tolerate it and may snap because it hurts. I really want Denim to have the best and safest grooming experience possible. Any help or guidance you can provide would be greatly appreciated.