I switched from Sprint to Mint last December. I tried all the instructions but wifi calling doesn't work, likely because my Galaxy S7 was originally bought from Sprint. Recently I start working from home due to the coronavirus, and rely more on my mobile phone. Then I realized that people often have trouble calling me and I have trouble making calls too (the phone attempts to call, then just ends quickly by itself). I often have to enable airplane mode and then disable it, to refresh the connection. Even the successful calls take like 10 seconds to get connected. All these issues makes it basically unusable. Is there any solution to this? I prepaid 12 months, so I still have 8 months left. Is it possible to return and get a prorated refund?