Our understanding is that purchasers can pull out of their purchase until the point at which the habitation licence is issued. If you have now passed that point, and you have not said in which Block you purchased, your options are limited to selling or renting out, short or long term.
The market for sales is slow at the moment ,and there are a number of units that have been up for sale for several months now. The long term rental market, however,seems to be buoyant . We moved out of a rental in Phase 3 on the Monday to move into our Phase 4 purchase and new tenants had moved in within 36 hours. In Block 1 a completion took place on the Monday and a long term tenant moved in the following weekend.
A scan of the ads in the local press indicates that the rental cost of a 2 bedroom rental on Arenal seems to be in the range of 650-800 euros a month depending on size, location and whether it is furnished or un-furnished. Your rental income will need to cover not only your mortgage, but community fees, the local council and basuro taxes and any obligations you might have to pay the Spanish wealth tax. You will also need to take into account agency fees if you use the services of a rental company.
Perhaps your best option would be to put your apt up for sale but to rent it out on a six monthly contract in the meantime.
Hope this helps in terms of what must be a difficult decision for you.
Ken&Jenny German