Help getting Padron address

My husband and I hired lawyers in Madrid to get a non lucrative visa. We had to be in Spain in January. We've been here 3 weeks in Begur. The law is we have to be registered with an address in 30 days after arrival. The lawyers told us we could travel to Madrid, pay them more money than we already did, and they would give an address and we could register in Madrid, although we are trying to find a place in Begur area. Now they just told us the Padron appointments are booked up til April! 🤬 We have to leave March! Not sure why that wasn't mentioned by the lawyers! Now I'm concerned our visas will be ruined. We tried to pay locals to get an address to register,  but it seems foreigners have done this and left the country without changing their address, so no luck. Anyone have any advice, know local lawyers, or a person we could pay for an address to register? We are looking for a place to eventually buy. Thanks!