Telnyx line comparability with AT&T incoming calls

Hi. I have had a serious problem for the past week and a half because i can't call my pharnacy. It started about a week and a half ago, never had the problem before, calling pharmacy for years. The pharmacy is Rite Aid, only one location near me has this problem, i can call other Rite Aids, the business number is 818 907 1431. When i call this number, which has always worked fine, the receiving number disconnects the call, no connection. This is with both my cell and land phones. They are both AT&T, i don't have a problem calling any other number. ATT said the problem is not with ATT. They did an investigation and said that the problem is with the pharnacy's phone company which they said is Telnyx. They told me that Telnyx is not handling AT&T's calls corrrectly, They said they were getting other calls from customers about this. what does that even mean? more important , no one has said it outright yet but the implication is that it can't be fixed, ATT did all they could, i was told . My phone lines are fine, like always, Apparently ATT can't reach out to Telnyx to correct harms to customers and the only outcome is that i have to drive in my car to go to the pharmacy to ask information about my prescriptions, did they receive them? when might they be ready? The pharmacy can call me and text me, but there's no contact number they can give me to call them, other than the one that disconnects me. I'm leaving now to drive to the pharnacy again just to ask them for information, im driving there for the 3rd tine to just ask a question. Rite Aid said they haven't heard of this problem from any other customer, no one is accountable. No one is responsible. I have no idea who to contact. Is this sub reddit a source of information and trouble shooting about this kind of problem? If not, does anyone know if there is another place where this problem is being discussed in social media? thanks for listening to my travails .